Evolution of transitional behavior and structure of electron-irradiated poly(vinylidene fluoride-trifluoroethylene) copolymer films

The effect of high-energy electron irradiation on poly(vinylidene fluoride- trifluoroethylene) (PVDF-TrFE) copolymer is investigated in a broad range o f electron doses in light of a recent finding of the relaxer ferroelectric behavior and large electrostriction in the material. It is shown that altho ugh irradiation reduces both the crystalline and polar ordering, the two ar e not directly related to each other. In contrast to differential scanning calorimetery (DSC) and X-ray results which show that the copolymer becomes amorphous for higher irradiation dose, the dielectric data still exhibit re laxation peak which follows the Vogel-Fulcher law, indicating the presence of local polar ordering. (C) 2001 Published by Elsevier Science B.V.