Dynamics of glass-forming liquids. IV. True activated behavior above 2 GHz in the dielectric α-relaxation of organic liquids

C. Hansen, F. Stickel, Ranko Richert, E. W. Fischer

Research output: Contribution to journalArticle

104 Citations (Scopus)

Abstract

We have measured the dielectric relaxation of butylbenzene and of the glass-former propylbenzene in the frequency range 10-2 Hz to 2×1010 Hz in order to characterize the variation of relaxation times with temperature for these low loss liquids. Additionally, salol has been remeasured above 1 GHz with improved resolution. Using the sensitive data representation [-d log10(fmaxHz)/ d(1/T)]-1/2 vs 1/T we find demarcation temperatures TA, at which the temperature dependence changes from a Vogel-Fulcher type law within the limits TB≤T≤TA to Arrhenius behavior for T>TA, corresponding to a position of the loss peak fmax>2 GHz. The activation energies derived from dielectric relaxation data for T>TA are associated with the energy of vaporization, Eη ∝ΔEvap. A comparison of dielectric relaxation times τD to viscosity data in this wide range of temperatures suggests the relation τD∝η/T rather than τD∝η.

Original languageEnglish (US)
Pages (from-to)6408-6415
Number of pages8
JournalJournal of Chemical Physics
Volume108
Issue number15
StatePublished - Apr 15 1998
Externally publishedYes

Fingerprint

organic liquids
Dielectric relaxation
Glass
glass
Liquids
liquids
relaxation time
Relaxation time
Temperature
temperature
frequency ranges
Vaporization
viscosity
activation energy
temperature dependence
Activation energy
Viscosity
energy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Dynamics of glass-forming liquids. IV. True activated behavior above 2 GHz in the dielectric α-relaxation of organic liquids. / Hansen, C.; Stickel, F.; Richert, Ranko; Fischer, E. W.

In: Journal of Chemical Physics, Vol. 108, No. 15, 15.04.1998, p. 6408-6415.

Research output: Contribution to journalArticle

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