In this work, the dynamics of the primary a- and the Johari-Goldstein (JG) b- processes are studied with dielectric spectroscopy. We found the relaxations at glass transition temperature in polyphenylglycidyl- ether and diglycidyl ether of bisphenol-A to be strongly correlated over a wide temperature T and pressure P range. Analysing the temperature and pressure behaviour of the a- and (JG) b-processes, a clear correlation has been found between the structural relaxation time, the Johari-Goldstein relaxation time and the dispersion of the structural relaxation.
Key words: Dielectric relaxation, nano-size motion, polyphenylglycidyl-ether (PPGE),diglycidyl-ether of bisphenol-A (DGEBA).
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