A Model of Structural Relaxation in Glass

TLDR

Structural relaxation in glass is complicated by memory effects and inherent nonlinearity. The study introduces a multiparameter model of structural relaxation that incorporates these effects. The model predicts glass properties under arbitrary temperature‑time histories by accounting for memory and nonlinearity. The model fits experimental data on property evolution after temperature steps and can aid in designing heat‑treating processes such as annealing.

Abstract

Study of the time dependence of physical properties in the transformation range of glass is complicated by the “memory effect” and the inherent nonlinearity which are characteristic of structural relaxation. A multiparameter model of structural relaxation is presented that differs from earlier models in that it takes account of both these effects. This model fits available experimental data well; these data were obtained for the most part by observing the evolution of properties (such as density or refractive index) following a step change in temperature. The present model also permits prediction of the physical properties of glass subjected to arbitrary and more complex temperature‐time histories. It should, therefore, also be useful in the rational design of heat treating processes such as annealing.