The broadband dielectric spectra of both polymers exhibit
rich dynamic processes, which are affected by the
random introduction of the CFE in the polymer chains
and by the sample treatment conditions. In the temperature
range investigated (from −150 to 120◦C), the copolymer
exhibits at least four dielectric anomalies. The ferroparaelectric
phase transition occurs at 110◦C (measured
on heating). It does not depend on frequency and exhibits
a large thermal hysteresis, a reflection of a first
order transition process. Dynamic relaxation of polymer
chains at the crystalline/amorphous interface gives rise to
a weak dielectric dispersion βc at temperatures from −20
to 40◦C, depending on frequency, which is also visible
in the relaxor terpolymer.