ABSTRACT
This chapter presents the chemical composition, manufacturing methods, and essential properties of glasses. In optics manufacturing, many optical materials are used: plastics, crystals, liquids, gradient index materials, glass ceramics, and glasses. Due to the wide range of available refractive indices, the latter represent the most important and commonly used optical materials. Optical glasses can be classified into two main categories: single-component glasses and multicomponent glasses. Prime examples of single-component glass are quartz glass and fused silica, which exclusively consists of silicon dioxide. Multicomponent glasses that are mainly used in optics manufacturing consist of network formers, network modifiers, and stabilizers. The basic cross-linked glass matrix is formed by the network formers whereas network modifiers alter the glass composition and its optical properties, respectively, and additionally reduce the melting temperature. Optical glasses can be manufactured by flame pyrolysis or by classical melting; the latter method is usually applied for high volumes.
