β Scribed by F. Stickel; F. Kremer; E.W. Fischer
No coin nor oath required. For personal study only.
The scaling of the dielectric and electric relaxation in two low molecular weight glass forming systems (PDE = Phenolphtalein-dimethylether and KDE = Kresolphtalein-dimethylether) is studied in the frequency regime from 10m3 Hz to lo9 Hz by use of broadband dielectric spectroscopy. For both the dielectric a-relaxation and the dc-conductivity the temperature dependence is characterised by a crossover (at a temperature T,) from an Arrhenius to a Vogel-Fulcher-Tammann law. Above T, the dc-conductivity (reflecting translational diffusion of mobile charge carriers) and the a-relaxation have the same temperature dependence. Below T, a decoupling is found in agreement with recent tracer diffusion experiments (M. Lohfink and H. Sillescu, in: Proc. of the 1st Tohwa University Int. Symp., Fukuoka, Japan, 4-8.11.1991, Am. Inst. Phys. Conf. Series). For the a-relaxation, the relaxation time distribution shows a pronounced temperature dependence below TA, while it is only weakly varying with temperature above TA.
π SIMILAR VOLUMES
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