AbstractThe frequency, temperature, and hydrostatic pressure dependences of the dielectric properties, molecular relaxations, and phase transitions in PVDF and a copolymer with a 30 mol% trifluoroethylene were investigated. The β‐relaxation peak temperatureTβand the melting temperatureTmof both polymers, and the ferroelectric transition temperatureTcof the copolymer, are strong increasing functions of pressure. The magnitudes of the pressure derivatives ofTβ,Tc, andTmincrease in the order of the “transition” temperatures, i.e.,Tβ(P)