Borosilicate glass is a type of glass that includes at least 5% boric oxide. The boric oxide makes the glass resistant to extreme temperatures, and also improves its resistance to chemical corrosion. This glass is very popular in the manufacture of scientific instruments, and it was once widely used to make glass for kitchens as well. Today, soda-lime glass is the glass of choice for kitchenware, due to the fact that it is generally cheaper to produce.
Usage
Borosilicate glass's refractory properties and physical strength make it ideal for use in laboratories, where it is used to make high-durability glass lab equipment, such as beakers and test tubes. In addition, borosilicate glass warps minimally when exposed to heat allowing a borosilicate container to provide accurate measurements of volume over time.
During the mid-twentieth century borosilicate glass tubing was used to pipe coolants (often distilled water) through high power vacuum tubebased electronic equipment, such as commercial broadcast transmitters.
Glass cookware is another common usage; a borosilicate glass pie plate is almost the American standard pie dish. Borosilicate glass measuring cups, featuring painted-on markings illustrating graduated measurements, are also widely used in American kitchens.