What should be paid attention to when disassembling the glass door of the display cabinet?

Does the glass door of the refrigerator have high requirements for glass? Let's take a look at some properties of glass: Isotropic glasses have irregular molecular arrangements and spatially statistically homogeneous molecules. Ideally, the physical and chemical properties of homogeneous glass (such as refractive index, hardness, modulus of elasticity, coefficient of thermal expansion, thermal conductivity, electrical conductivity, etc.) are the same in all directions. There is no fixed melting point, and since glass is an amorphous mixture, there is no fixed boiling point.

The change of glass from solid to liquid is carried out in a certain temperature range (ie softening temperature range), which is different from crystal materials and has no fixed melting point. The softening temperature scale is TG?T1, TG is the transition temperature, T1 is the liquidus temperature, and the corresponding viscosities are 1013.4 DPA·s and 104?6dpa·s respectively.

Metastable glassy materials are usually obtained by rapidly cooling the melt.

When they change from a molten state to a glassy state, the viscosity increases dramatically during cooling, and the particles do not have time to arrange themselves regularly to form crystals without releasing the latent heat of crystallization. Therefore, the internal energy of the glassy material is higher than that of the crystalline state, and its energy is between the molten state and the crystalline state, which belongs to the metastable state.

From a mechanical point of view, glass is an unstable high-energy state, for example, there is a tendency to change to a lower-energy state, ie, there is a tendency to crystallize.

Therefore, glass is a metastable solid material. The change of physical and chemical properties is continuous and stepwise. This is obviously different from the crystallization process of the melt.

New phases will appear during the crystallization process, and many properties will suddenly change near the crystallization temperature point. Glassy materials from a molten state to a solid state are accomplished over a wide temperature range. As the temperature is gradually lowered, the viscosity of the glass melt gradually increases, forming a solid glass, but no new phases are formed in the process.

In contrast, the process of heating and melting glass is also gradual.