The melting and recrystallization behaviour of the microstructure in both plasticized and rigid poly(vinyl chloride) (PVC) has been examined using temperature-dependent small-angle X-ray scattering and small-angle neutron scattering. PVC plaques plasticized using dioctyl phthalate have been studied within the temperature range 90-195-degrees-C. The results are interpreted in terms of the fringed micelle model.