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Prevalence of approximate [formula] relaxation for the dielectric α process in viscous organic liquids.
- Source :
-
Journal of Chemical Physics . 4/21/2009, Vol. 130 Issue 15, p154508. 15p. 1 Chart, 12 Graphs. - Publication Year :
- 2009
-
Abstract
- This paper presents dielectric relaxation data for organic glass-forming liquids compiled from different groups and supplemented by new measurements. The main quantity of interest is the “minimum slope” of the α dielectric loss plotted as a function of frequency in a log-log plot, i.e., the numerically largest slope above the loss peak frequency. The data consisting of 347 spectra for 53 liquids show prevalence of minimum slopes close to -1/2, corresponding to approximate <RADICAL><RADICAND>t</RADICAND></RADICAL> dependence of the dielectric relaxation function at short times. The paper studies possible correlations between minimum slopes and (1) temperature (quantified via the loss peak frequency); (2) how well an inverse power-law fits data above the loss peak; (3) degree of time-temperature superposition; (4) loss peak half width; (5) deviation from non-Arrhenius behavior; (6) loss strength. For the first three points we find correlations that show a special status of liquids with minimum slopes close to -1/2. For the last three points only fairly insignificant correlations are found, with the exception of large-loss liquids that have minimum slopes that are numerically significantly larger than 1/2. We conclude that—excluding large-loss liquids—approximate <RADICAL><RADICAND>t</RADICAND></RADICAL> relaxation appears to be a generic property of the α relaxation of organic glass formers. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 130
- Issue :
- 15
- Database :
- Academic Search Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 38020823
- Full Text :
- https://doi.org/10.1063/1.3098911