MODEL FOR DYNAMICS OF STRUCTURAL GLASSES

We have studied, using dynamical Monte Carlo methods, a facilitated ki netic Ising model for structural glasses. We observe stretched-exponen tial decays (alpha relaxation) of the equilibrium spin autocorrelation function at late times and are able to estimate accurately the corres ponding relaxation times tau. These are found to diverge at nonzero te mperatures following a Vogel-Fulcher law. In addition, we observe earl y-time exponential relaxation analogous to beta relaxation of glass fo rmers. We also examined the effective thermodynamics of systems quench ed below this divergent temperature and subsequently heated. The resul t is a peak in the specific heat with properties matching those of the putative glass transition. We also find that these peaks, for differe nt heating rates, can be rescaled to lie on a universal curve. Finally , we studied the evolving structure factor of a frozen glass following a rapid jump in temperature. The results are qualitatively the same a s those for x-ray studies of heated glasses. We thus demonstrate that this purely dynamical microscopic model can reproduce much of the phen omenology of the glass transition and near-glass relaxation, with no t unable parameters.