The time evolution of the pyroelectric response induced by a laser pulse irradiation in a VDF/TrFE copolymer

The pyroelectric response induced by a YAG laser pulse irradiation has been measured over a bread range of 1ns-10s for a VDF/TrFE copolymer with composition 75/25 mol%. The time spectra contain two damped oscillations associated with thickness and length extension mode piezoelectric resonance. Removing such components by means of Fourier analysis has revealed two kinds of pyroelectric responses, the instantaneous component appearing prior to thermal expansion and the gradually increasing component reflecting fluctuations of crystalline dipoles.