Test of the entropy basis of the Vogel-Tammann-Fulcher equation. Dielectric relaxation of polyalcohols near Tg

C. A. Angell, D. L. Smith

Research output: Contribution to journalArticle

202 Scopus citations

Abstract

We describe a family of hydrogen-bonded molecular liquids in which transport processes all appear to be strongly coupled and which exhibit relaxation times conforming to the Vogel-Tammann-Fulcher (VTF) equation τ = τ0 exp(B/[T - T0]) over as much as 12 orders of magnitude in τ. For such systems a stringent test of the identity of the VTF equation T0 and the Kauzmann isoentropy temperature TK can be made. New data on dielectric relaxation times extending into the glass transformation range are presented for three polyalcohols, and heat capacity data for crystalline and liquid ethylene glycol are also reported. Estimates of the Kauzmann temperature, TK, at which the internally equilibrated supercooled liquid would have the same entropy as the crystal, are made. Despite a threefold variation in TK, these are found to be close to the best-fit VTF equation T0 parameter and even closer to the T0 value obtained by adding the constraint B = 12.7T0 to the analysis.

Original languageEnglish (US)
Pages (from-to)3845-3852
Number of pages8
JournalJournal of physical chemistry
Volume86
Issue number19
DOIs
StatePublished - Jan 1 1982
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

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