The Relation between the Physical Properties and the Structure of Glass. Part II. Viscosity as a Function of Temperature

JSGT 1947 V31 T074-T089

It has been shown that the variation of the physical properties of glass with time, in certain ranges of temperature, can be explained on the assumption of a random structure for glasses. This random network has an equilibrium configuration for each temperature. The equilibrium configuration is established instantaneously at sufficiently elevated temperatures. At lower temperatures the physical properties vary with time on account of the time taken to reach equilibrium configuration. The logarithm of the viscosity of normal liquids is inversely proportional to the absolute temperature, but the viscosity of glass cannot be so expressed as a function of temperature. It is shown that the viscosity­–temperature relationship of glasses call be predicted from the same assumptions of a random network structure which possesses an equilibrium configuration for each temperature. It is possible, therefore, to reconcile X-ray diffraction data, the variation with time of the physical properties and viscosity–temperature relationships for glasses with the same model for glassy structures.

 
R. W. Douglas