| Autor: |
Ransom TC; Naval Research Laboratory, Chemistry Division, Code 6100, Washington, DC 20375-5342, USA., Casalini R; Naval Research Laboratory, Chemistry Division, Code 6100, Washington, DC 20375-5342, USA., Fragiadakis D; Naval Research Laboratory, Chemistry Division, Code 6100, Washington, DC 20375-5342, USA., Roland CM; Naval Research Laboratory, Chemistry Division, Code 6100, Washington, DC 20375-5342, USA. |
| Abstrakt: |
Dielectric relaxation measurements, in combination with density determinations, on tetramethyl tetraphenyl trisiloxane (DC704) over an unusually broad range of temperatures and pressures revealed a state-point dependency in its density scaling exponent. This is the first unambiguous experimental demonstration of a breakdown of density scaling in a nonassociated glass-forming material, and unanticipated for DC704, among the "simplest" of liquids, having a constant breadth of the relaxation dispersion and a Prigogine-Defay ratio near unity characteristic of approximate single-parameter systems. We speculate that the anomalous behavior has origins in the large value of its scaling exponent and relative flexibility of the chemical structure. |
