Heat Resistant Glass
Glass considered to be heat resistant is able to withstand high heat and sudden temperature change without shattering or cracking. These qualities are obtained through post-forming heat treatments or element additives that increase the glass temperature resistance. Heat resistant glass is used in industrial, construction, cooking and laboratory applications where high temperatures would cause standard glass to shatter. Fire resistant windows, stove top and cooking surfaces, fireplace screens, laboratory equipment and cookware are all made from heat resistant glass. Borosilicate, soda-lime, glass-ceramic and quartz glass are all either considered heat resistant glass or are able to undergo heat treatments. The brand name Pyrex is a common type of cookware glass that is oven and stove top safe.
Glass that doesn't shatter when exposed to high heat or rapid temperature change has a low thermal expansion coefficient; that is, a number that delegates how much the material expands and contracts when heated or cooled. Borosilicate glass, which is standard glass with boron oxide added, is naturally a heat resistant material, as is quartz glass, which is made from pure silicon. Soda-lime glass is standard glass, and it becomes heat resistant when tempered. Tempering is a post-forming process where glass shapes are heated. This causes the internal parts of the glass products or shapes to contract and the surface tension to increase, resulting in a better balance of stresses in the glass. Glass ceramic is heat treated until crystals begin to form in the glass. Fire resistant construction glass panels or panes are generally made of soda-lime glass that has been glazed with glass-ceramic or a construction of two panes of soda-lime glass that have fire-retardant material inside.