NONEQUILIBRIUM AND HYSTERETIC LOW-TEMPERATURE DIELECTRIC RESPONSE TO STRAIN IN GLASSES

We present data on the nonequilibrium ac dielectric response of amorph ous insulators to the application of a quasi-de mechanical str ain fie ld below 150 mK. The behavior of the system after perturbation by a st rain field is analogous to that observed after the application of a dc electrical field. In the current theoretical framework the nonequilib rium response is due to a time dependent density of states correction resulting fi om TLS-TLS interactions, In addition, an anomalous hyster esis in fast strain and electric field sweeps is reported which may re present the predicted dynamical response of relaxing independent TLS.