ABSTRACT
By most definitions, glass is an amorphous, inorganic solid derived by the melting and rapid cooling of a mixture of raw materials typically composed of silicates, phosphates, borates, and carbonates. The manufacture of glass dates to at least 1500 B.C. in the Egyptian and Mesopotamian civilizations. Today, glass has become one of the most versatile materials available with applications ranging from microelectronics to heavy construction. The most commonly manufactured glasses are those of the soda-lime family. These glasses are predominantly composed of the oxides of sodium, calcium, and silicon, with varying additions of aluminum, magnesium, and potassium oxides. These are the common window and container glasses, but also include fiberglass and lamp bulbs. Another facet of the industry deals with specialty glasses; these are glasses compositionally tailored to have properties specific to an application and typically produced in lower volumes. A subset of the specialty glass industry deals with materials referred to as glass-ceramics. These materials begin their life as glasses, melted and formed as a glass, then through a secondary heat treatment they are allowed to partially crystallize, giving them properties similar to, and in many applications, superior to ceramics (1).
