Investigation of Iodine-Doped Poly(Ethyl Methacrylate) Relaxation by TSDC Technique in the Vicinity of the Glass Transition Temperature

Corona poling and thermally stimulated depolarization current (TSDC) techniques have been used to study the relaxation behavior of pure and iodine-doped poly(ethyl methacrylate) (PEMA) in the vicinity of the glass transition temperature (Tg). Different parameters, such as corona field and corona temperature, have been used. The global TSDC spectrum of pure PEMA with varying poling field and poling temperature revealed that pure PEMA is characterized by only a single relaxation peak located at T = 349 K. On the other hand, iodine-doped PEMA samples are characterized by two distinguished relaxation peaks. The first one has been observed in the temperature range from 347 K to 363 K, whereas, the second one has been detected at a higher temperature, T ∼ 395 K. The origin of the TSDC peaks is attributed to a superposition of dipolar relaxation and space-charge build up. Thermal sampling (TS) technique was used to get more information about the fine structure of pure and iodine-doped PEMA samples.