Borosilikatglass

Borosilicate glass is a family of glass types in which boron oxide (B2O3) is added to silica (SiO2). This modification lowers the glass’s coefficient of thermal expansion and improves resistance to thermal shock, making it a preferred material for heat-exposed and chemically aggressive environments. Typical formulations include a major fraction of SiO2, about 7–13% B2O3, and smaller amounts of alkali and alkaline earth oxides, along with alumina to adjust viscosity and durability.

Key properties include a low coefficient of thermal expansion (around 3 x 10^-6 /K), high resistance to thermal shock, good chemical durability, and optical clarity. It remains formable at high temperatures but can devitrify if overheated or improperly processed. While more resistant to many chemicals than soda-lime glass, borosilicate glass is still attacked by hydrofluoric acid and certain strong bases under aggressive conditions.

Manufacture and forms: produced by standard glassmaking processes using boron-containing batches; homogeneous melting and careful refining to avoid crystallization; can be formed into tubes, flasks, beakers, and other shapes for laboratory and industrial use. It is commonly sold as annealed glass; some applications involve coatings, tempering, or specialized glass-ceramic variants for higher strength.

Applications and history: borosilicate glass is widely used in laboratory glassware, chemical reactors, optical components, and cookware. It originated in the late 19th century through the work of German chemist Otto Schott, and has since become a staple in science and industry due to its combination of clarity, thermal stability, and chemical resistance.