Thermochimica Acta, 226 (1993) 65-75 Elsevier Science Publishers B.V., Amsterdam 65 DSC and TSC study of a VDF/TrFE copolymer’ G. Teyssedre, A. Bernes and C. Lacabanne * Solid State Physics Lab., Paul Sabatier University, 31062 Toulouse Cedex (France) (Received 11 November 1992; accepted 20 April 1993) Abstract The semi-crystalline 75/25 mol. % P(VDF/TrFE) copolymer has been studied by thermo- stimulated current (TSC) spectroscopy. The analysis of the fine structure of the complex TSC spectrum has revealed that the relaxation mode associated with the glass transition has two components: the lower temperature component is characterized by relaxation times obeying a compensation law with T, = T, + 25°C and has been associated with the glass transition of the true amorphous phase of the copolymer; the upper temperature component has been attributed to the constrained amorphous phase. The mode observed at highest temperature is characterized by a compensation phenomenon with a compensation temperature corresponding to the Curie transition temperature. Therefore, it has been associated with the ferro/paraelectric transition of the crystalline phase. INTRODUCTION Polyvinylidene fluoride (PVDF) and its copolymers with tri- fluoroethylene (TrFE) have been extensively studied because of their ferroelectric properties. Copolymers of -50~SOmol.% VDF are of great interest, firstly because they crystallize directly in the p -ferroelectric phase, and secondly because they exhibit a ferro/paraelectric, or Curie, transition below the melting point. The purpose of this work is to investigate relaxation phenomena associated with transitions in a 75/25 mol.% P(VDF/TrFE) copolymer. Comparative studies of transitions, by differential scanning calorimetry (DSC), and of the dielectric relaxations, by thermostimulated current (TSC) spectroscopy, have been performed. * Corresponding author. ’ Presented at the 21st Annual NATAS Conference, Atlanta, GA, 13-16 September 1992. 0040-6031/93/$06.00 0 1993 - Elsevier Science Publishers B.V. All rights reserved