Monolithic glass formation by chemical polymerization
Historically, glasses have been formed by solidification of oxide melts from elevated temperatures. Recently it has been demonstrated that monolithic oxide glasses can be formed by chemical polymerization at low temperatures. By the use of this technique, high-temperature reactions such as crystallization, phase separation, etc., which restrict glass formation in certain systems and regions, can be largely avoided. Thus, the technique not only permits investigation of glass structure from a fundamentally different point of view, but also allows the formation of new glasses which can not be formed by thermal means.
In this work, the nature of inorganic network formation by chemical polymerization is described. The method of preparing polymerizable active species in a soluble state and general considerations that must be observed to prevent incoherent self-condensation of glass-forming species during hydrolysis and polymerization are discussed. Certain characteristic properties of materials formed by chemical polymerization are also included.