Glassy properties
1. Isotropic: Because glass has a statistically uniform structure, it has the same numerical properties in different directions, such as refractive index, hardness, elastic modulus, and dielectric constant, and it has birefringence without internal stress.
2. Soften gradually during heating: from brittle state to plastic state, high viscosity state, and finally melt, the viscosity changes continuously.
3. Melting and solidification are reversible: repeated heating to the molten state, and heating and solidification according to the same system, if no phase separation and crystallization occur, the original properties will be restored.
4. The internal energy of the glass state is larger than that of crystals: Under the proper temperature conditions, glass has a tendency to crystallize. At temperatures below the liquidus, glass crystals are spontaneous and do not require external work.
5. The properties of the glass change continuously with the composition within a certain range: This can change the composition to change the properties of the glass. For example, ordinary silicate glass is an insulator, but chalcogenide glass is a semiconductor. The conductivity of As2Te3 is as high as 27 ° C. 10s / m.