ABSTRACT
Both modern glass and modern optics grow largely from one of the great historic coincidences, the coming together in the town of Jena in Germany in the year 1880 of three great giants—the university physicist Ernst Abbe, the lensmaker Carl Zeiss, and the ceramic scientist Otto Schott. Devitrification is defined as the formation of a crystalline phase when glass is held at a critical temperature for a long enough time. Abbe wrote a book Refracting and Dispersing Power of Solid and Fluid Bodies and formulated the physical requirements for optical glasses which were needed to design a variety of high quality and novel photographic and scientific instruments. The properties of glass are determined primarily by its formulation and secondarily by the details of the processing to which that formulation is subjected. Silica is the outstanding glass forming oxide because of its resistance to devitrification, resistance to attack by water and most acids, and low coefficient of expansion.
