and the interval of the transition becomes wider while corresponding amounts of enthalpy of dipole contribution increases these changes improve the pyroelectric properties of the material the increase in the polarity corresponds to the increase in capacitance i e ability to hold electric charge fig3 shows a comparison of the dsc thermograms for ferroelectric to paraelectric phase transition comparing purified and annealed copolymer versus purified but non annealed after the purified film has been annealed the shift of the ferroelectric to paraelectric peaks is not very significant fig4 shows a comparison of the dsc thermograms for melting temperature of annealed and non annealed purified copolymers upon review of the non annealed results of fig1 there is only one phase transition peak at about 78 u00b0 c for the purified copolymer thus the purified non annealed p vdf trfe has a transition temperature approximately 10 u00b0 c higher than that of the unpurified copolymer and slightly higher than that of the annealed purified copolymer to summarize the test results of fig1 to 4 ferro electric polar to para electric non polar transition in purified material show only one peak whereas unpurified material has two the total area of two peaks in the unpurified copolymer corresponding to a simple phase transition plus ferroelectric transition is more than that of the single.