Glass

Glass Chemistry

Besides to usage of ceramics in laboratories glass [glassware] also used in the different laboratories. Other places where glass is used include windscreens of cars, windows in houses, furniture, television sets, soft drink bottles, water drinking glass, and spectacles

Glass is an amorphous solid material that exhibits a glass transition. It is a state of matter in which the atoms and molecules are locked into place, but instead of forming neat, orderly crystals, they arrange themselves randomly.

Glass is having similarity with ceramics in terms of their properties like durability, strength and brittleness, high electrical and thermal resistance, and lack of chemical reactivity.

Glass is made up of silica (SiO2). Following are the other components of silica

Sodium oxide
Magnesia
Lime
Alumina
Boric oxide
Soda (Na2O)
Lead oxide
Potassium oxide
Zinc oxide
Barium oxide
Germanium oxide

Glass chemistry

History of glass

First true glass was made in coastal north Syria

The story of glass dates back to ancient Egypt where glass-making became popular during the late Bronze Age.

Anglo-Saxon period glass was a luxury material across England

In 10th centaury stained glass came to usage

In 1330 crown glass was produced in Rouen

In 14th and 19th centauries stained glass employed in building purposes

In 1843 Henry Bessemer invented float glass

In 120th centaury reinforced glass and glass bricks came to usage

Colored glasses are due to inclusion of ions of chemical elements like iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), chromium (Cr), and manganese (Mn)

Glass preparation

Glass production

The main constituent of flat Glass is SiO2. This has a high melting temperature in the region of 1700 degrees C. The basic building block of silica has a tetrahedral pyramid shape with silicon at its centre linked symmetrically to four oxygen atoms at its corners.

On cooling molten silica quickly, a random organised network of these tetrahedra is formed, linked at their corners, to give an amorphous material known as vitreous silica.

High melting point and viscosity of silica can be reduced by the addition of sodium oxide. Here sodium oxide works as flux. Sodium oxide used in the form of a carbonate and the sodium-oxygen atoms enter the silicon-oxygen network.

These network modifiers make the structures more complex so that when the components are melted together. In the glass making process, the cooling rate is arranged such that viscosity increases and the mobility of the atoms are hindered thus preventing arrangements and crystallization from occurring.