Stress and time dependence of relaxation and the Kohlrausch stretched exponent formula

A general non-linear description of the kinetics of relaxation is derived. Existing phenomenological approaches are extended introducing model considerations of the flow-stress behavior of a system. Particular attention is given to the stress and time dependence in the kinetics of relaxation. It is shown that the empirical Kohlrausch stretched exponent formula is an approximation to dependences following from the Prandtl-Eyring potential energy barrier model of viscous flow of matter.