On the statistics of dense,disordered assemblies: Equilibrium and dynamics

We consider implications of a lattice model which operates with a vacancy fraction h as a measure of structural disorder. Consequences for the configurational thermodynamics of one- and multicomponent systems and their phase equilibria are briefly indicated. The principal topic is the glassy state under steady state conditions, as well as the kinetics of relaxational processes toward equilibrium. The central role of the h-function in its dependence on variables of state is made evident among others by the connection between equation of state and thermo-elastic properties. Moreover, a dynamics of volume relaxation can be treated by means of a corresponding theory for the h-function. Applications of this theory to isothermal annealing below the glass temperature T_g, the response to a constant cooling rate of the melt through the transition zone, and the computation of a complex compression modulus are reviewed. The implications of vacancy cluster distributions for the analysis of positron spectroscopy are pointed out. Finally we indicate the basis for the development of correlations between T_g and structural parameters.