What is borosilicate glass?

 

The borosilicate glass has a very low coefficient of thermal expansion, which is only about one third of that of ordinary glass. This will reduce the effects of temperature gradient stress and thus have stronger fracture resistance. Due to its very small shape deviation, it makes it an indispensable material in telescopes and mirrors, and it can also be used to treat highly radioactive nuclear waste. Even if the temperature suddenly changes, the borosilicate glass is not easily broken. When broken, the borosilicate glass will have large cracks instead of being pulverized into particles. At the same time, borosilicate glass also has low dispersion and relatively low refractive index.