Window glass has a lifespan. Do you know how long it is?

01Common glass

There is no "aging" problem in the natural environment. The chemical composition of glass is very stable, in the natural state of glass will not be affected by sunlight, rain and fog performance attenuation; Ordinary acids and bases do no harm to glass, as we can see from our school chemistry lab ware.

Generally, there are only two conditions that affect the life of glass: humid air and high temperature. Continuous humid air can make glass mildew, but at room temperature, the speed of glass mildew is very slow, generally need a few months of time, in the normal use of the environment rarely have a few months of humid air, so the glass exposed in the air is not mildew. General glass mildew occurs in the glass overlap storage process, glass in the wet warehouse or open pile rain is more prone to mildew. Generally speaking, untempered glass is more likely to mold than tempered glass.

The temperature below 300℃ has no effect on the life and chemical stability of glass without considering the factors of thermal cracking. But above 300℃, the physical and chemical properties of glass will change with the increase of temperature. Physically speaking, glass begins to soften at about 600 degrees. Chemically speaking, rising temperatures cause crystallization inside the glass, gradually turning it from transparent to fuzzy. The process of glass crystallization and loss of transparency takes several days at 700℃, and may take months or even years at 300℃. At room temperature, the glass crystallization becomes fuzzy may need tens of thousands of years, so it can not be considered.

02Toughened glass

Physical tempering is heating the glass and then quenching, changing the structure of the molecules inside the glass and between the molecules; Chemical tempering is used to carry out ion exchange on the molecular structure of glass surface at high temperature. Both methods permanently alter the microstructure of the glass material. Therefore, unless there is a high temperature and hardening effect, the characteristics of the tempering under normal use will not decay or change with time.

03Hollow glass

Insulating glass is a combination of glass substrate, spacer frame (aluminum strip), desiccant (molecular sieve), sealing material (butyl adhesive, polysulfide adhesive or structural adhesive). In the composition of insulating glass, glass and aluminum frame is usually very stable, and the life of insulating glass depends on the life of molecular sieve and sealing material.