This study focuses on the effect of thermal history on the morphology of poly(vinylidene fluoride). Rheophotoacoustic Fourier transform infra-red spectroscopy (RPA FTi.r.) was utilized to measure changes in PVDF network permeability as a function of elongation. The permeability data, in conjunction with the stress-strain response, provide insights into the morphological changes resulting from deformations. The rate at which the PVDF network is cooled from the melt, as well as morphological changes resulting from annealing, appear to have a substantially greater influence on the response of the network to deformations than molecular weight effects. Prior to deformations, the crystalline phase and the size of the individual crystals, appear to have the most effect on PVDF permeability. Following the application of stresses, the number of tie molecules have a dominating effect on the network permeability. Annealing PVDF within 20 degrees C of its melting point (170 degrees C) increases the yield stress and the Young’s modulus values. Similar effects are detected upon reducing the cooling rate.