Retardation and flow at the glass transition

The crossover from back-and-forth jumps between structural minima to the no-return jumps of the viscous flow is modeled in terms of an ensemble of double-well potentials with a finite decay probability. The ensemble is characterized by the Kohlrausch-exponent β of the time dependence t(β) of the response at short times. The model is applied to shear and dielectric data from the literature.