THEORY OF GLASS-TRANSITION - CHEMICAL-EQUILIBRIA APPROACH

The main principles of a chemical approach to the analysis of glass-forming melt structure and its change with temperature are formulated. It is shown that such an approach leads to the concept of the existence of chemical groupings in melts. The use of the basic equations of chemical thermodynamics provides conclusions about the temperature dependences of structural changes in glass-forming melts. Taking into account the highly probable dependence of the activation energies of structural relaxation on temperature and the distribution of relaxation times values which is inevitable for any amorphous substance, one can develop an algorithm to obtain a good fit between the calculated and experimental dependences of properties. In principle, this algorithm nearly coincides with that for the phenomenological Tool-Narayanaswamy model. Thus the approach described can be considered as a theoretical foundation for this model.