AbstractThe relations between stress, strain. and time in the tensile creep under constant load of polyvinyl chloride plasticized with dioctyl phthalate have been studied experimentally over a range of temperatures and compositions. It is concluded that existing theories are not adequate to deal with large strains, nonequilibrium conditions, and a distribution of relaxation times. The variables stress, strain, and time may be separated at low loads for “soft” compositions but not for “hard” compo