COOPERATIVE RELAXATIONS TRANSITIONS IN FERROELECTRIC POLYMERS

Dielectric relaxation and thermal transitions in beta-PVDF have been i nvestigated by Thermo-Stimulated Current spectroscopy and Differential Scanning Calorimetry respectively. A comparative study of spectra and thermograms has been performed. The relaxation mode associated with t he glass transition of the true amorphous phase is characterized by re laxation times obeying a compensation law due to cooperative molecular movements. A conformationally disordered structure is proposed for be ta-PVDF to explain thermal events occurring around 60-degrees-C. Agein g of ferroelectric properties of beta-PVDF has been associated with co operative molecular movements liberated largely below the melting poin t.