The Viscosity–Temperature Relationship and Some Inferences on the Nature of Molten and of Plastic Glass

JSGT 1932 V16 T244-T253

The author has subjected to examination the equations of G. Fulcher & E. N. de C. Andrade, which endeavour to establish a relationship between viscosity and temperature in the case of glasses. From the actual viscosity measurements of S. English & H. R. Lillie on soda–lime–silica glasses the conclusion is drawn that at temperatures lower than that at which log₁₀η=8, the glasses are either non-associated or that the degree of association has become constant. At higher temperatures, the curve obtained by plotting log₁₀η against the inverse of the absolute temperature departs from linearity and the author interprets this as due to the process of dissociation setting in. After examining equations suggested by Andrade and J. Frenkel for associated liquids, the author deduces an alternative equation which represents the viscosity–temperature relationships for the glasses tested by English, Lillie, and R. F. Proctor, and R. W. Douglas. In the case of the soda–boric oxide–silica glasses, the author concludes that the degree of association increases as the boric oxide content increases. No evidence was found of the existence of an “aggregation temperature” suggested by Fulcher.

S. C. Waterton