Slow dynamics of salol: a pressure and temperature dependent light scattering study

摘要

We study the slow dynamics of salol by varying both temperature and pressureusing photon correlation spectroscopy and pressure-volume-temperaturemeasurements, and compare the behavior of the structural relaxation time withequations derived within the Adam-Gibbs entropy theory and the Cohen-Grest freevolume theory. We find that pressure dependent data are crucial to assess thevalidity of these model equations. Our analysis supports the entropy-basedequation, and estimates the configurational entropy of salol at ambientpressure ? 70% of the excess entropy. Finally, we investigate the evolution ofthe shape of the structural relaxation process, and find that atime-temperature-pressure superposition principle holds over the rangeinvestigated.