Glass

Glass, an amorphous substance made primarily of silica fused at high temperatures with borates or phosphates. Glass is also found in nature, as the volcanic material obsidian and as the enigmatic objects known as tektites . It is neither a solid nor a liquid but exists in a vitreous, or glassy, state in which molecular units have disordered arrangement but sufficient cohesion to produce mechanical rigidity.

Glass is cooled to a rigid state without the occurrence of crystallization; heat can reconvert glass to a liquid form. Usually transparent, glass can also be translucent or opaque. Color varies with the ingredients of the batch.

Glass generally refers to hard, brittle, transparent material, such as those used for windows, many bottles, or eyewear. Examples of such materials include, but are not limited to, soda-lime glass, borosilicate glass, acrylic glass, sugar glass, isinglass (Muscovy-glass), or aluminium oxynitride.

In the technical sense, glass is an inorganic product of fusion which has been cooled through the glass transition to a rigid condition without crystallizing. Many glasses contain silica as their main component and glass former

Glass plays an essential role in science and industry. The optical and physical properties of glass make it suitable for applications such as flat glass, container glass, optics and optoelectronics material, laboratory equipment, thermal insulator (glass wool), reinforcement fiber (glass-reinforced plastic, glass fiber reinforced concrete), and art.