Comparison of Empirical Criteria of Glass Annealing and the Relaxation Theory of Glass Transition: What is the Better for Practical Purposes?

On the boundary of centuries it is useful to summarize of our knowledge in area of glassy state generally and, in particular, what we do know about the influence of heat treatment of a glass to its properties. In the given paper the analysis of known models, existing in the literature, of property modifications in these conditions is shortly made. Besides the paper discussed the physical meaning of some empirical constants found by Adams and Williamson (A) for annealing process constructing and shown correlation between them and physical property values used by modern relaxation theory of glass transition (RTGT).
It is well-known that residual stresses result from the combined effect of transient thermal stresses during cooling and its relaxation in the glass transition range. During the last 100 years (as far as I can suppose Benjamin F. Biser published the first paper on this theme: "The Principles of Annealing as Applied to Glass Excerpted from Elements of Glass and Glass Making" on 1899) a number of theoretical approaches has been developed to calculate stresses in glass during its cooling. The modern simulation of structural relaxation and RTGT based on the Tool-Narayanaswamy (T) model had been the subject of numerous studies. Now RTGT can be and have to use not only for glass annealing. It seems this theory is more accurate and more effectively then A because RTGT predicts property changing of glasswares after any heat, pressure and/or chemical treatments. Genetically connected both A and T approaches compared here based on the temperature dependence of glass viscosity which defines the same dependence of structural and stress relaxation times and temperature distribution across the wall thickness of glassware as well. The main ideas of RTGT were further developed into the contemporary relaxation theory by efforts of many scientists. Specially important contribution were made by Gardon and Narayanaswamy and Volkenshtein and Ptitsin.

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The Authors

Dr. Yurii Startsev Dr. Institute of Silicate Chemistry R. A. S. Appreciable contribution to the development of practical applications of glass transition theory was developed with O.V.Mazurin. I tried to improve of experimental technique and to measure of some pro... Read more