Crystal Growth and Glass Formation

Abstract

Our concern in the present paper will be directed primarily to a kinetic treatment of glass formation, with some additional attention paid to the crystallization behavior of binary alkali silicate liquids. The problem of glass formation has been considered from several points of view, with attention being focused on various aspects of the problem by different investigators. Structural, thermodynamic or kinetic factors have been suggested by different workers to be decisive in the glass-forming behavior of materials. Our own preference for the kinetic approach is based not only upon its potential for developing quantitative treatments of glass-forming behavior, but also upon the consideration that glass formation (i.e., the formation of amorphous solids) seems primarily to involve considerations which are kinetic in character. It is well known, for example, that at least sore glass-formers are known in every category of material based on type of bonding, including metallic, Van der Waals, hydrogen, ionic and covalent. Further, it seems that nearly any liquid will form a glass if cooled sufficiently rapidly to a sufficiently low temperature, and will form a sensibly crystalline or partly crystalline body if cooled too slowly.