Quartz glass is divided into linear expansion and bulk expansion. The expansion and contraction curves of quartz glass are uniform. The reversible hot blood resistance of quartz glass is one of the important properties of quartz glass. Quartz glass is far more resistant to high temperature than any other kind of glass. Its melting temperature is above 1713℃, softening temperature 1580℃±10℃, annealing temperature 1140 ℃± 20℃. High temperature use, opaque quartz glass can be used at 900℃ high temperature. Quartz glass is glass composed of pure silica.

Quartz glass is usually divided into the same name quartz glass and opaque quartz glass two categories. Quartz glass has high purity and good chemical stability. The content of silica of opaque quartz glass is more than 99.5%, the content of silica of transparent quartz glass is more than 99.97%, and the content of silica of high purity quartz glass is more than 99.999%. The silica content of quartz glass produced by direct gas refining of silica tetroxide can reach more than 99.9999%.

The physical and chemical properties of quartz glass The optical high permeability is undoubtedly expressed by its structure. Many scholars have done a lot of research on the structure of quartz glass, Landal theory proved that the composition of quartz glass is simple, and is made up of (SiO4) silicon oxygen tetrahedron. Thus it is shown that the structure of quartz glass is similar to that of quartz at high temperature, only the arrangement of silico-oxygen tetrahedrons is different, the arrangement of silico-oxygen tetrahedrons of quartz glass is irregular, because of the different dissolution method of quartz glass, the structure of the expression is different. Quartz glass contains impurities and the structure is also related, so the structure of quartz glass is very complex.