DYNAMICS OF DIPOLAR GLASSES - ELASTIC AND DIELECTRIC-PROPERTIES

We have formulated a model for the coupled dynamics of the local polar ization and the elastic deformations of dipolar glasses. Randomly inte racting dipoles undergo a phase transition to a glassy state, which is signalled above Te by a divergence of the relaxation time of the dipo lar autocorrelation. Dipolar dynamics is directly observable in the dy namic dielectric susceptibility, for which we predict a power law depe ndence on frequency at and close to T-c. The slowing down of dipolar d egrees of freedom also gives rise to dynamic critical anomalies in the elastic and structural properties, like the appearance of a central p eak and divergence of the sound damping. All these phenomena are a con sequence of dynamic scaling of the dipolar autocorrelation and hence i nterrelated. We discuss two scaling functions in detail: One is calcul ated within mean field theory and the other one is taken from numerica l simulations of short range Ising spin glasses. The predictions of th e model are in accordance with most experimental findings for dipolar glasses.