Study of the relaxation processes of amorphous poly(Ethylene-Terephtalate) by isothermal depolarization currents.
Abstract
In order to characterize the dielectric relaxation of Poly(EthyleneTerephtalate) around and below Tg, both isothermal and thermally stimulated currents (IDC and TSC) have been carried out. The experimental results are interpreted on the basis of the coupling model. The coupling strength parameter β is calculated at different temperatures below Tg from IDC measurements between -150 and 60^circC and from TSC spectra obtained at various heating rates in the temperature range -160 to 88^circC. Following a previously described experimental procedure (E. Marchal J. Chem. Phys. 105, 6068, (1996)), the isothermal depolarization measurement is completed by a temperature induced accelerate depolarization in order to estimate without loss of information the remaining polarization and to take into account the relaxation time of slower processes. The analysis of IDC data using a fitting of the depolarization current and using the relaxation time procedure proposed lead to the same value of β. A good agreement is observed between the values of β obtained from IDC and TSC measurement in the temperature range -150 to 60^circC.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.Q3834M