Structural relaxation in the glass: Evidence for a path dependence of the relaxation time

Using a recently developed novel temperature perturbation experiment, one of the primary assumptions underlying the phenomenological models of structural recovery, i.e., that the relaxation time depends on the instantaneous state of the material and not on its temperature history, is tested. The results of our experiments show that as the material gets close to equilibrium, this assumption is valid, but far from equilibrium, it is not.