Schröter, K. et al.:
Dielectric spectroscopy in the αβ Splitting Region of Glass Transition: Different
Evaluation Methods and Experimental Conditions
Schröter, K.; Unger, R.; Reissig, S.; Garwe, S.; Kahle, S.; Beiner, M.; Donth, E.:
Dielectric spectroscopy in the αβ Splitting Region of Glass Transition in
Poly(ethyl methacrylate) and Poly(n-butyl methacrylate): Different Evaluation Methods
and Experimental Conditions,
Macromolecules 31 (1998) 8966–8972,
DOI: 10.1021/ma9713318.
Stability of the dielectric parameters in the αβ splitting region against methodical variations is demonstrated. The Williams product ansatz for correlation functions and an additive ansatz for dielectric functions are compared for poly(ethyl methacrylate). Both evaluation methods give a diminishing α intensity with increasing temperature, and a separate trace for the α relaxation different from both the secondary β relaxation below and the high-temperature a process above the crossover. Furthermore, measurements on different poly(n-butyl methacrylate) samples and evaluation results of different experimentalists are compared. The intensity onset of the cooperative α relaxation, starting from zero at a characteristic temperature Ton in the crossover region, and the parallel course of α and β relaxations below Ton, separated by about one frequency decade in an Arrhenius diagram, remain stable against measurement and evaluation variations.