Discontinuities in the physical properties of supercooled liquids

Abstract

The viscosity, electrical conductivity and density of several liquids have been measured over a range of temperatures both above and below the melting-point. The results confirm that the activation energy of viscous flow is greater in the supercooled state than in the normal liquid, the slope of the log η , 1/ T graphs increasing by about 10% on passing into the supercooled region. In the series of liquids formed by co-ordinating boron trifluoride to acetic acid and its methyl, ethyl, n -propyl and n -butyl esters the effect increases with the chain length of the alkyl radical. A similar discontinuity in the log k , 1/ T curves indicates that the activation energy for ionic migration is also greater in the supercooled than in the normal state. Although this discontinuity in electrical conductivity has not been noted previously, it is shown to be implied in the numerical results of earlier authors. In contradistinction to viscosity and electrical conductivity, the density varies linearly with temperature over the whole range. These results are discussed in relation to the published data on the other physical properties of supercooled liquids.

Dissociation Pressures and Phase Equilibria of the Pentafluoroanisole-- Boron Trifluoride Complex System.

“…The molar volume of pentafluoroani so.le calculated by equation (44), using a molecular weight of 198.093 g. and a density of In each table the calculated pressures were obtained by using the appropriate constants for the indicated compositions from Table XV, page 115, and Table XVI, …”