High borosilicate glass (also known as hard glass), the glass composition contains high borosilicate, boron: 12.5~13.5%, silicon: 78~80%, so this type of glass is called high borosilicate glass. The glass is made by using the characteristics of glass to conduct electricity at high temperature, and it is melted by heating inside the glass and processed by advanced production technology. Because the linear thermal expansion coefficient is (3.3±0.1)×10-6/K, it is also called "borosilicate glass 3.3". It is a special glass material with low expansion rate, high temperature resistance, high strength, high hardness, high light transmittance and high chemical stability. Because of its excellent performance, it is widely used in solar energy, chemical industry, pharmaceutical packaging, and electric light sources. , Craft jewelry and other industries.