The materials definition of a glass is a uniform amorphous solid material, frequently produced when a suitably viscous molten material cools very fast to below its glass transition temperature, thereby not giving enough time for a regular crystal lattice to form. A simple example is when table sugar is melted and cooled quickly by dumping the liquid sugar onto a cold surface. The resultant solid is amorphous, not crystaline like the sugar was initially, which can be seen in its conchoidal fracture.
The word glass comes from Latin glacies (ice) and corresponds to German Glas, M.E. glas, A.S. glaes. Germanic tribes used the word glaes to describe amber, recorded by Roman historians as glaesum. Anglo-Saxons used the word glaer for amber.
The remainder of this article will be concerned with a specific type of glass—the silica-based glasses in common use as a building, container or decorative material.
In its pure form, glass is a transparent, comparatively strong, hard-wearing, essentially inert, and biologically inactive material which can be created with very smooth and impervious surfaces. These desirable properties lead to a great many uses of glass. Glass is, however, brittle and will break into sharp shards. These properties can be modified, or even changed completely, with the addition of other compounds or heat treatment.
Common glass is frequently amorphous silicon dioxide (SiO2), which is the same chemical compound found in quartz, or in its polycrystalline form, sand.
Glass You On Here » Glass
