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Abbreviated Journal Title

Phys. Rev. E

Keywords

Supercooled Liquids; Temperature-Dependence; Relaxation; Viscosity; Orthoterphenyl; Diffusion; Behavior; Region; Physics; Fluids & Plasmas; Physics; Mathematical

Abstract

Measurements of the enthalpy relaxations in liquid orthoterphenyl in the supercooled state have been carried out using specific-heat spectroscopy over the frequency range from 2 Hz to 6.3 kHz, as a function of temperature and as a function of pressure. The observed α-relaxation peaks in the phase of the complex specific heat show increasing relaxation times τ with increasing pressure at constant temperature, similar to the divergence of τ when the calorimetric glass temperature Tg is approached by lowering the temperature at constant pressure. The temperature and pressure dependence of the measured mean relaxation times τ¯ near Tg are in remarkable agreement with those found by other spectroscopic methods and have been compared with an extended Vogel-Fulcher-Tammann law. However, we find different scaling when the glass transition is approached by cooling or by increasing pressure. This suggests that the assumption of a simple volume-activated process is not adequate.

Journal Title

Physical Review E

Volume

51

Issue/Number

6

Publication Date

1-1-1995

Document Type

Article

Language

English

First Page

5899

Last Page

5904

WOS Identifier

WOS:A1995RE08200086

ISSN

1063-651X

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