1. The thermal expansion coefficient of high borosilicate glass is different from that of ordinary glass

Borosilicate glass has a very low coefficient of thermal expansion, about one-third of that of ordinary glass. This will reduce the impact of temperature gradient stress, resulting in stronger fracture resistance. Due to its very small shape deviation, this makes it an essential material in telescopes and mirrors. It can also be used to dispose of high-level nuclear waste.
The borosilicate glass begins to soften at about 821 ° C (1510 ° F), at which temperature the type 7740 viscosity high borosilicate is 107.6 weights.
2, the main composition of high borosilicate glass and ordinary glass is different
Ordinary glass is sodium calcium silicate glass, is a kind of silicate glass, its chemical composition is Na2O·CaO·6SiO2, the main component is silica; The main components of high borosilicate glass are boron trioxide and silicon dioxide, which are added to water glass sand, soda water and ground lime in the manufacturing process of ordinary silicate glass. The boron content and silicon content of high borosilicate glass can reach 14% and 80% respectively, while ordinary glass generally does not add boron.