Slow secondary relaxation process in supercooled liquids
Physikalisches Institut, Universität Bayreuth, D-95440
Accepted: 30 October 1997
We report on dielectric susceptibility measurements for the glass-forming systems toluene and 1-propanol, both of which exhibit slow secondary relaxation (Johari β-process). We present a complete lineshape analysis for both α- and β-process covering the real and imaginary parts. The observation of secondary relaxation in the rigid molecule toluene shows that this process is not of intramolecular origin. The β-process is well resolved in the supercooled liquid and in the glass. Above Tg a strong temperature dependence of the relaxation strength is observed. For the activation energy of many glass-forming systems we find the relation .
PACS: 64.70.Pf – Glass transitions / 77.22.Gm – Dielectric loss and relaxation / 61.43.Fs – Glasses
© EDP Sciences, 1997