Fullerton et al v. Corelle Brands, LLC et al

Northern District of Illinois, ilnd-1:2018-cv-04152

Exhibit Ex. B - Shattering Glass Cookware article

Interested in this case?

Current View

Full Text

Case: 1: 18 - cv - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 1 of 8 Pageld #: 233 EXHIBIT B Case: 1: 18 - CV - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 2 of 8 Pageld #: 234 - - - - - - - - - Case: 1: 18 - CV - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 3 of 8 Page | D # 235. . . . . . . . . - * * * * * - - se * * · - * * * * * * * * * * og er athri et Apple * V. . & * - Washi Remnants of soda lime silicate * glass cookware failure, from Consumer Reports testing, * * . . . K w me Credit: CorrsurTer Reports. . . . . . . . . . . m D - 3464 Pa r Shat glass cookware R. C. Bradt and R. L. Martens Exploding or shattering glass cookware sur faced as an issue of concern during the past two decades, and reports of problems have been chron icled in several news stories. Collectively, the accumu lated complaints suggest that there may be a fracture problem with some glass cookware products. However, none of the coverage has specifically addressed the scientific aspects of the reported failures. This article examines the technical aspects of the sudden, explo sion - like failure of glass cookware products. Background Coming Inc. pioneered the development and market for glass cookware. The glass cookware products originally manufactured by Coming were made of a low thermal expansion borosilicate glass eventually marketed as Pyrex. (Many glass scientists also associate the name Pyrex with the original borosilicate glass products. Even today, Coming still produces high - quality borosilicate laboratory glassware under the name and trademark of Pyrex .) The originai Pyrex cookware was promored as " oven to icebox " or " ice box to oven " cookware, presumably because the low coefficient of thermal expansion of the borosilicate glass made it highly resistant to the thermal stresses that develop during these types of temperature changes. Corning retains the Pyrex registered trademark, but, in 1994, the company began licensing other companies to manufacture products under the Pyrex brand (see " Froin battery jars to kitchens: A short history of glass cookware, " page 35) . Today, the Pyrex brand is manufactured for consumer markets in the US, North America, South America and Asia by World Kitchens LLC (Rosemont, Ill .) under a license from Coming. A separate company, Arc Intemational (Arques, France), ' manufactures and markets Pyrex brand cookware for the European, Middle East and African consumer markers. Independently, the Anchor Hocking Glass Company (Lancaster, Ohio) makes its own line of glass cook ware, and has been doing so for many decades under its own brand names. thinus SMARTVITTAAMIS - The shattering of glass cookware in house hold kitchens has been reported in Consumer Reports articles, ' . 2 television documentaries, complaints to the United States Consumer Products Safety Commission and internet post ings. This article examines the issue from a three fold technical perspective: (i) reviewing the reported scenarios of the incidents, which are suggestive of thermal stress fracture; (ii) comparing the thermal shock resistance of borosilicate glass with soda líme silicate glass and (iii) examining new and broken glass cook ware. Together, these related perspectives sug gest the thermal stresses that develop during temperature changes are the primary cause of the explosion - like breakages. The substitution of higher thermal expansion soda lime silicate glass for borosilicate glass in the manufacturing is a contributing factor. IR125L SKU2. 07. WEBrico Compositions of glass cookware According to the World Kitchens website, Corning changed to a soda lime silicate composition for the glass cookware, and this is the Pyrex tech nostas ' Exploding and shattering have been applied interchangeably in reports describing cookware fractures because of accounts of glass shards beina propelled for some distance. The term " explosion as applied here is not the same as the pressure explosion of a carbonated beverage container. American Ceramic Society Bulletin, Vol. 91, No. 7 | www. ceramics. org. - - - - - - L (PYREX Document #: Clased: 09 / 06 / 18 Page 4. 0f. & Page ! D #: 236. den Shattering glass cookware de Bijenkort 44. 790915 $ 197 2 134 w L. - - _ LAV. ETIC. . . . . * * * * k o * uluisa * * * . . A HIV. . . 14A 3,, Sunli M S IPUA, . . * * * . . . . . . S. . . . 1 - Di. - - - - TV - - £14 extensive handling of glass cookware, it is expected that surfaces will become damaged or scratched over time. With these provisos noted, the focus of the authors has been to isolate the effects resulting from thermal stress. What follows below focuses only on che thermal shock properties of the two glass types. Generally speaking, thermal stress fracture of glass is not an uncommon event. For example, impingement of bright sunlight on a portion of large windows can cause them to crack from the shady cold edge, and cold water splashing on Figure 1, An Arc International label for its Pyrex glass cookware products, from cookware purchased in Europe. hot glass marine light covers frequently fractures them. Much is known and understood about thermal stresses and thermal nology that World Kitchens (then Borden) bought from shock fracture. ! ! The nature of the published reports of the Coming in 1998. World Kitchens acknowledges thar the shattering incidents with the soda lime silicate glass cook glass cookware ir markets under the Pyrex brand name is ware suggests a thorough consideration of thermal stresses made from a soda lime silicate glass composition. because the failure incidents are often associated with signifi On its own, Anchor Hocking developed a " me too " line of cant temperature changes. lt cookware that also is based on a soda lime silicate glass. The documented and reported glass cookware incidentsit These soda lime silicate glass cookware products appear suggest that the thermal stress resistance of present day to be commercial successes. However, they are not made of soda lime silicate glass cookware is less than thar of low a low thermal expansion, thermal stress resistant borosilicate expansion borosilicate glass, such as the original Pyrex. For glass as originally developed by Corning. example, some of Arc International produces a line of glass cookware prod the glass cookware ucts. These are of a borosilicate glass composition, which items have been ir markets with the phrase " Authentic Pyrex " on the label reported to frac (Figure 1) . " ture immediately The three companies that currently manufacture glass on a change in cookware - World Kitchens, Anchor Hocking and Arc temperature, while International - use different silicate glass chemistry formula other cookware tions. The authors confirmed this by examining the glass fractures occur dur chemistry formulations used in the products from each of the ing a short time three companies using energy dispersive spectroscopy on a after removing the FEI Quanta 200 3D scanning electron microscope equipped cookware with with an X - ray analyzer Model Apollo XVF from EDAX. The its contents from Arc Internarional cookware was determined to be a boro a hot oven. (See silicate glass with a distinctive, readily identifiable boron Consumer Reports peak. It evidently is the original Corning Pyrex composition, example, Figure 2 .) The tests confirmed, as expected, that neither the World Fractures thar occur Kitchens nor the Anchor Hocking products are borosilicate at a time interval glasses, but are soda lime silicate glasses of slightly different after a temperature compositions. The chemical spectra clearly show the boron change, such as peak in the Arc International glassware, but the World after removal of the Kitchens and Anchor Hocking glassware are free of boron. cookware from a They are distinguishable by their calcium and magnesium hot oven, are char peaks. acteristic of ther mal stress failures. Indications of thermal stress fracture of glass However, there cookware also are reports of Before going further, two things should be noted. First, failure while the the manufacturers of soda lime silicate glass cookware claim cookware with its that it has superior mechanical strength and is less likely to contents is inside Figure 2. Heat test: Frames from video fracture on impact, for example by dropping it, a nor unrea che oven. These of tests conducted by Consumer Reports ' sonable concem in kitchen settings. Second, because of the thermal gradients shows bakeware made of sodo lime sili may have differ cate glass shattering after being heated in * * The authors were not able to find any reports of Arc International Pyrex cookware ent origins, such 450°F degree oven and placed on a wet failing in an explosive manner. as mighe develop countertop. - . - - ZARAT - - - . . . . . . . . . . . . .:, . .:: . (Creuit. Consumers Union) . istit i. . 34 www. ceramics. org | American Ceramic Saciety Bulletin, Vol. 91, No. 7 W rena Case: 1: 18 - CV - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 5 of 8 Pageld #: 237 if frozen contents are placed in the cookware before being inserted into a hot oven. As described in Introduction to Ceramics, by Kingery, Bowen and Uhlmann, ' 2 delayed thermal stress fractures will often occur after temperature changes. This is because the maxi - mum thermal stress is achieved only as a temperature gradient develops after the temperature change. That delay time for thermal stress fracture depends on the heat transfer conditions of the cookware and the heat capacity of the contents within For example, preparing a roast, a chicken or a ham in a glass cookware dish would each have different heat capacities and present different heat transfer conditions, and the cooking temperatures of their surroundings would be different as well. Therefore, time delay intervals to fracture are expected to vary. The reports that the soda lime silicate glass cookware experiences these delayed shattering fractures suggests that the thermal stresses that develop exceed its strength. The time dependence of thermal stresses is a function of the heat transfer conditions during the temperature change. These factors determine the magnitude of the temperature gradients and cause the thermal stresses. For example, trans ferring a hot dish containing a roast directly from the oven to a cold wet stone countertop would be a much more severe thermal shock than putting the same dish on an insulating pad surface. Because it is impossible to consider all of the possible variations that might occur in household kitchens, a simple, linear elastic approach to a sudden temperature change is applied to estimate and compare the thermal stress resistance of the two glasses As noted in Kingery, Bowen and Uhlmann, ' the simple formula for the fully restrained development of a linear elas tic thermal stress, O, from temperature change is = EAT (1) From battery jars to kitchens: A short history of glass cookware where a is the coefficient of thermal expansion, E the elastic modulus and AT the temperaçure differential over which the thermai stress or thermal expansion restraint is generated. The AT may occur during either heating or cooling. Note that this simple estimate does not include the heat transfer factors, nor time factors, nor does it account for the size and shape of the glass cookware pieces in question. Equation (1) is applicable to an instantaneous, rapid temperature change. To compare the thermal shock fracture resistance of boro silicate and soda lime silicate glasses, Equation (1) is rear ranged to express the AT values required to achieve fracture by the thermal scresses generated in the glass cookware dur ing a temperature change. These AT values can be compared with typical cooking temperatures and other temperature changes that are regularly encountered in a household kitch en. Equating on to the fracture stress of the glass, or, then rearranging Equation (1) yields AT = 0, aE (2) Today, glass cookware is found in virtually every household kitchen, giving the impression that it has been around a very long time. Many older consumers still associate the Pyrex brand with the Corning company, and most consumers are unaware that the manufacturers of Pyrex and the glass formulation have changed over several decades. Glass cookware is a commercial product of the early 20th Century. Present - day glass cookware appears to have originated from research at what was then known as the Corning Glass Works to improve the thermal shock resistance of battery jars. Corning developed a low - thermal - expansion borosilicate glass that vastly improved the longevity of the battery jar glasses by reducing their thermal shock fracture in service. It is an interesting scenario how this glass found its way into household kitchens. During the research studies, one of the Corning scientists, Jesse Littleton, took the bottoms of several of Corning's borosilicate glass jars home for his wife to bake her pies. Her successful culinary endeavors led to the development of a line of cookware and laboratory glassware by Corning that became known as Pyrex. It was initially called " Py - right, " with an obvious " pie " to spy " phonetic association. The glass, itself, was originally called Nonex (NON - EXpanding) . This glass appears to have evolved into the famous low - expansion Corning 7740 (tradename Pyrex) and other Corning borosilicate glasses, In 1997, the company sold its consumer products business, including Pyrex - branded consumer products, to Borden Inc. (now KKR Borden), which changed its name to World Kitchens in 2006. Coming stift owns the Pryex trademark, and it still manufac tures Pyrex - branded high - quality laboratory borosilicate glass ware. However, most glass cookware in the United States is not the same borosilicate composition as the original Corning Pyrex. where the thermal stress, g, is now on the failure strength of the glass object. A typically used benchmark value for glass strength, as noted by Mould ') and also by Kurkjian ! 4 is about 5, 000 pounds per square inch (about 30 megapascals) . The elastic moduli of the two glasses are slightly different, but similar about 10, 200, 000 psi (about 68 gigapascals) for soda lime sili cate glass and about 9, 100, 000 psi (about 62 gigapascals) for borosilicate glass. 15 Their coefficients of thermal expansions are very different. The a of borosilicate is about 3 x 10 - 60C ? . The a of soda lime silicate glass is abour 9 X 10 ^ °C, about three times greater. 15 Substituting these values into Equation (2) yields the AT values of the rapid temperature change necessary to initiate thermal shock fracture. For borosilicate glass, the calculated temperature difference is about 183°C (about 330°F), but it is only about 55°C (about 99°F) for the soda lime silicate glass. This is a substantial difference. Carter and Norton, is in their text Ceramic Materials, Science and Engineering, use a somewhat more complicated American Ceramic Society Bulletin, Vol. 91, No. 7 į www. ceramics. org Antal - Case: 1. 18 - CV - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 6 of 8 PageID #: 238 Shattering glass cookware glass form of Equation (1) that includes heat transfer terms. They water. Consistent with these calculations, the October 2011 address many ceramics as well as glasses. Their results will be Consumer Reports article describes a boiling water incident compared with the calculations of this simple approach. The that led to explosive fracture of a measuring cup and an QEAT term is common to all mathematical models. accompanying injury, Carter and Norton provide an example (which includes Based on recipes in the famous cookbook, The Joy of heat transfer terms), estimating thermal stress AT values for Cooking, by Rombauer, Becker and Becker, ' * these calculated fracture that are about 270°C (about 486°F) for the boro AT values of concern are well within the temperature ranges silicate Pyrex and about 80°C (about 144°F) for soda lime of kitchen cooking endeavors. For example, their recom silicate głass. Based on these two independent results, it is inended oven temperatures are 350°F for a pork loin or rib evident that the temperature differential - - the AT for frac eye roast (after 450°F preheat) and 325°F for a turkey (after ture initiation by severe thermal stress - is much larger for 450°F preheat) . Relative to room temperature, these cook the borosilicare glass. ing temperatures could easily exceed the expected AT values A brochure posted on Corning's websiteli presents thermal for the thermal stress fracture of soda lime silicate glass and stress resistance estimates of several glasses of various compo - could cause thermal shock fracture. sitions, including its 7740 borosilicate glass and a soda lime The AT value alone does not guarantee thermal fracture of silicate glass (Corning 0080) . The reported thermal stress glass cookware. However, because of the low AT for soda lime resistance value for the borosilicate glass is 54°C (97°F), silcate glass, one must exercise extreme caution when using whereas that of the soda lime silicate glass is 16°C (29°F) - a cookware made of this glass. Even at modest kitchen tempera factor of about three. Thermal stress resistance is defined for tures, there is a definite possibility of thermal shock fracture. this calculation as " the temperature differential between two surfaces of a tube or constrained place that will cause a ten Heat strengthening of soda lime silicate glass caak sile stress of 0. 7 kg / mm (1000 psi) on the cooler surface. " ware It is important to note that, according to this brochure, In Consumer Product Safery Commission correspon the primary use of 0080 is Petri dishes, not household cook dence, ' CPSC's Saver Products. gov website and literature ware. Also, it must be noted that soda lime silicate glass relative to shattering glass cookware, manufacturers have compositions vary widely, and values of thermal properties responded that during manufacturing they have taken steps will vary, too. However, these data illustrate the magnitude to strengthen the soda lime silicate glass cookware by apply. of the difference in thermal srress resistance that is possible ing a heat strengthening or a thermal tempering process. The between the two categories of glasses. The superior thermal manufacturers assert that the process increases the strength stress resistance of borosilicate glass for cookware was con of the glass, its impact resistance and its resistance to thermal firmed in empirical tests performed on glass cookware objects stress fracture. 19 by Consumer Reports. l. . This strengthening approach is discussed by Mencik. . " In a It is informative to compare the AT values that have been related publication, Gardon i extensively reviews the anneal determined to achieve the fracture stress from the three ing and tempering processes, of which heat strengthening calculations. Table 1 lists those for the soda lime silicate is a variant. In principle, this approach has technical merit, glass and for Pyrex borosilicate. This tabulation shows that because increasing the glass cookware strength would be in every instance the AT for the soda lime silicate glass is expected to increase the AT values for thermal shock fracture much lower than that for the borosilicate. The difference is initiation. (Recall that the glass strength, o, is in the numer about a factor of three times for each despite the differences ator of Equation (2) for AT .) in the calculations. This is because the thermal expansion It is possible to detect residual stresses in glass via pho of the soda lime silicare glass is about three çimes that of the toelasticity. Thus, to test this heat - strengthening issue, the borosilicate. Clearly, soda lime glass is much more susceptible authors bought a half dozen new, unused soda lime silicate to thermal shock than the borosilicate glass because of its cookware pieces, which were then examined in the pho higher thermal expansion of coefficiene. toelasticity laboratory at the University of Alabama. The authors observed no strong fringe patterns, which would Table 1 Calculations of thermal differential, AT, for soda lime silicate: be indicative of residual stresses, in any of the cookware. and borosilicate glass. Although this could be the result of low - stress optic coef Source AT Soda lime silicate AT Pyrex borosilicate ficients of the soda lime silicare glasses, it also suggests This paper - 55°C (99°F) - 183°C (330°F) that the efficacy of heat strengthening that may have been Cartej and Norton ' s: - 80°C (1446) - 270°C (436°F) applied to the cookware during manufacturing was minimal Corning brochure ' ? - 16°C (297) - 54°C (97°F) and was not sufficient to significantly increase strength or thermal stress resistance of the soda lime silica cookware. From the perspective of kitchen applications, a good cali - It is well documented that thermally strengthened glasses bration point is that of boiling water, 100°C (212°F) ar sea also have a characteristic cracking pattern when they frac level. None of the calculations suggest the soda lime silicate, rure. Tempered glass breaks into small equiaxed pieces in glass would be likely to survive a rapid exposure to boiling a fracture process known as dicing. Automobile glass, for. . . Gi. . . . VJI, . . . . . 36 www ceromics. org American Ceramic Society Bulletin, Vol. 91, No. 7. . . . Case: 1: 18 - CV - 04152 Document #: 26 - 2 Filed: 09 / 06 / 18 Page 7 of 8 PagelD # 239 at S:, IN HE re - SAT YALAR mit UNA ADAT .:: u. . sen T Fracture origin. Credit: G. Quinn E RETAN S. example, fractures by dicing into small fragments. McMaster, Shercerly and Bueno ? depict this foron of fraginentation in their review, and creation of these dicing fragments has been analyzed in detail by Warren. ' The authors ' exarnination of fracture pieces of several dishes, including some that were intentionally broken by thermal stress and some by impact, revealed no dicing frag. mentation. The soda lime silicate cookware consistently frac cured into extended glass shards. The large shards produced by the fracture of the soda lime silicare cookware imply that the thermal or heat strength ening of the soda lime silicate cookware was not subscan cive. Figure 3 illustrates a reconstructed " Pyrex " bowl that was purchased new and intencionally thermal shocked in a household kitchen. There is no evidence of dicing fracture. The occurrence of long sharp glass shards is also described in numerous reports on the internet and in the CPSC litera ture. Another tool for evaluating whether there is significant heat strengthening of soda lime silicate glass is fractography, which can reveal information about the stress state of a frac tured piece. When a glass object with surface compressive stresses fractures, the propagating crack front in the glass proceeds ahead of the crack at the object surface because the near - surface advance is inhibited by the surface compressive stresses. 24 Indeed, the crack growth pattern on the fracțure surface of shards of soda lime silicate glass cookware, as shown in Figure 4, indicares that the soda lime silicate glass has been heat strengthened. Note the Wallner line ripples on the cross section clearly are trailing at the glass surfaces, indicative of surface compressive stresses. (Wallner lines are slighe ripples on a fracture surface that are indicative of the direcţion of crack propagation and the state of stress .) Thus, although the cookware definițely has been heat strengthened as stared by the manufacturer, ' ' it does not appear to be sufficient to increase substantially the thermal stress fracture resistance of the cookware, nor is it sufficient to create a desirable dicing fracture pattern for the glass cookware. Extensive, in - depth fractography of the fracture surfaces of shards from a large number or series of different reconstructed broken soda lime silicate cookware pieces would make it pos sible to identify the causes of individual failure events. Such studies, as described by Quinn ' in Fractography of Ceramics and Glasses, are recommended, but are beyond the scope of this article. Figure 3. A reconstructed soda lime silicate Pyrex bowl fractured by thermal shock. Arrows outline the crack paths. delay to fracture initiation after a temperature change; and (ui) calculared temperature differentials, the AT values for the initiation of thermal shock fracture during temperature changes of soda lime silicate and borosilicate glasses. In addi tion, the creation of fracțure shards instead of desired dicing of broken pieces of cookware suggests chat manufacturers ' hear strengthening is insufficient. Fracture - initiating temperature differentials can be exceed ed during household kitchen cooking. However, nor all kitch en procedures create AT values that are sufficient to cause thermal stress fracture of the soda lime silicare glass cookware. Time - dependent heat transfer conditions also will affect the magnitude of the thermal stresses that develop. The original Corning Pyrex borosilicate glass is consider ably more resistant to thermal stress fracțure than the soda lime silicate glasses that currently are used for most glass cookware products in the US. The estimated AT values for u kmawijay. cu. . . - . . - - V .: S. 7. . om LA CASA Crochi, Frachograph supplied by G Quinn. K Conclusions obout shottering glass cookware The above analyses of shattering soda lime silicate glass cookware indicate that the phenomenological cause of these fractures is chermal stress fracture that develops from temper ature changes to which the glass cookware is subjected in the household kitchen. This conclusion is substantiated by three observations: (i) occurrence of the shattering incidents dur ing temperature changes; (ii) the frequent presence of a time 1000 m Figure 4. The fracture surface of a soda lime silicate glass cook ware bowl (from bowl in Figure 3 } as it formed during thermal shock failure. Note the Wallner lines trailing along the surfaces, inside and out, are indicative of heat strengthening of the glass during manufacturing 22. www. hehehe. . . . American Ceramic Society Bulletin, Vol. 91, No. 7 | www. ceramics. org. . - Case: 1 - 18 - 66 - 24152 Document #: 26 - 2 - Filed: 09 / 06 / 18 Page 80f8 - PagetÐ - #: 240 Shattering glass cookware thermal stress fracture of that borosilicate glass suggest that normal kitchen cooking temperatures are unlikely to cause thermal stress failures. However, the estimated AT values for thermal stress fracture of soda lime silicate glass cookware are well within the range of kitchen temperatures. Estimates of the AT temperature differentials indicate chat soda lime silicate glass cookware can be expected to survive moderate temperature changes that are experienced in a household kitchen. However, documented reports of incidents of dramatic shattering failures during what most kitchen cooks would consider normal use suggests that the margin of safety for avoiding thermal stress failures of soda lime silicate cookware is borderline. It does not appear to be adequare for all household cooking. Caution is in order when using soda lime silicate cookware in applications that may involve temperature changes, as print warnings on the prod uct labels indicate. i SEOR moms make Acknowlegements The authors acknowledge the suggestions and assistance of M. Barkey, L. D. Pye, G. Quinn, S. Freiman, E. De Guire and P. Wray in the prepararion of this manuscript. Special chanks are exrended to G. Quinn for Figures 3 and 4. About the authors R. C. Bradt is the Alcon N. Scott Professor in the College of Engineering at the University of Alabama, Tuscaloosa, Ala. He presented an invited paper at ACerS Glass & Optical Materials Division meeting in 2011. He also has served as an expert witness in litigation cases involving glass cookware failures. R. Martens is manager of the Central Analytical Facility ar the University of Alabama. Contact: rcbradt @ eng. ua. edu References " Glass Bakeware that Shatters, " Consumer Reports, 44 - 48, January (2011) . 2 " Shattered Glass, " Consumer Reports, 40 - 42, October (2011) . Consumer Products Safety Commission, and the CPSC's SaferProdcuts. gov website, searched under " pyrex " and " glass cook ware. " * Intemet listings under " exploding pyrex. " National Institute of Standards and Technology, http: / / www. physics. nist. gov / cgi - bin / Star / compos. pl ? natno = 169. " M. B. W. Graham and A. T. Shuldinier, Coming and the Craft of Innovation, pp. 55 - 58. Oxford University Press, Oxford, UK, 2001. World Kitchens, Rosemont, lll. SARC International Cookware SAS, UI ARC International Cookware Lid ., France. Anchor Hocking Glass Co ., Lancaster, Ohio. Chtrp: / / www. pyrexware. com / index. asp ? pageld = 30 # TruchiD30, viewed 3 / 30 / 2012 " Thermal Stresses in Maurials and Scruclutes in Severe Thernal Environmenes. Edited by D. P. H. Hasselınan, et al ., Plenum, New York, 1980. 12W. D. Kingery, H. K. Bowen and D. R. Uhlmann, Introduction to Ceramics; pp. 816 - 844. Wiley, New York, 1976. 13R. E. Mould, " The Strengrh of Inorganic Glasses "; pp. 119 - 49 in Fundamental Phemonena in the Materials Sciences, Vol. 4. Edited by L .) . Bonis, $ .) . Duga and) . J. Gilman. Plenum, New York, 1967. 1 * C. R. Kurkjian, " The Mechanical Strength of Glasses - - - Then and Now, " The Glass Researcher, 11 [ 2 ] 1 - 6 (2002) . 15 Properties of Coming's Glass and Glass Ceramic Families. Corning Incorporated, Sullivan Park, Corning, NY, 1979. 16C. B Carter and M. G. Norton, Ceramic Materials, Science and Engineering; p. 633. Springer, New York, 2007. " http: / / catalog2. coming. com / Lifesciences / media / pdf / Thermai _ Properties _ of _ Corning Glasses. pdf, viewed 3 / 30 / 2012. 181. $ . Rombauer, M. R. Becker and E. Becker, Joy of Cooking. Scribner, New York, 1997 hotp: / / www. consumeraffairs. com / news04 / 2008 / 08 / pyrex _ response. html, viewed 3 / 30 / 2012. 203. Mencik, " Strength and Fracture of Glass and Ceramics "; pp. 250 - 57 in Elsevier Glass Science & Technology, Vol. 12. Elsevier, Amsterdam, Netherlands, 1992. 21 R. Gardon, " Evolution of Theories of Annealing and Tempering: Historical Perspective, " Am. Ceran. Soc. Bull ., 66 (11), 1594 - 99 (1987) . 22R. A. McMaster, D. M. Shecterly and A. G. Bueno, " Annealed and Tempered Glass "; pp. 453 - 59 in Ceramics and Glasses, Vol. 4, Engineered Materials Handbooks. American Society of Metals, 1991. 23P. D. Warren, " Fragmentation of Thermaily Strengthened Glass "; pp. 389 - 402 in Advances in Ceramics, Vol. 122. Edited by J. R. Vamer and G. D. Quinn. American Ceramic Sociery, Westerville, Ohio, 2000. 24V. D. Frechette, " Failure Analysis of Brittle Materials "; pp. 7 - 20 in Advances in Ceramics, Vol. 28. American Ceramic Society, Westerville, Ohio, 1990. 25G. D. Quinn, Fractography of Ceramic and Glasses, NIST Special Publication 960 - 16. US Government Printing Office, Washington, DC, 2007. . . . . . . - - - - . . . . - . - . - . - . - . - - - - - - - - COOK IN PURE, CLEAN GLASS ! SPICK * * SPAN i NO " PAN TASTE. . . NO " TYRHED - IN ! GREASE - WHIN YOU USE THIS SHINING, NON - FORQU $ COOKING WAKE DER - . i ' - DF V s et ! Wal PER You can stil P ta Want un c L. t. I ' L Th os 1. . * * 2 - 1 2 - ig. This. . . . ret W. " ixex - r p Af in K. i Urs M it + - D RA. B - 4. IT 1. 1 19 + Vito rhn. WE W A. . IN 5 l h. Cu Yed: L Din L G darbourly. What's Not to Bra e Toni t MET D on TAT. . . . IN DUAL; 14. 7 4. . . • • PYREX WARE. . . YOUR DEALER CAN SUOSEST MANY PYRO OIFE COMBINATIONS A 1936 adver tisement for the original Pyrex borosilicate glass cookware. turri bebas Jur. . . 38 www. ceramics. org American Ceramic Society Bulletin, Vol. 91, No. 7 Wa. . S.