On the dielectric susceptibility spectra of supercooled o-terphenyl.

Supercooled o-terphenyl has been the subject of many investigations including dielectric relaxation spectroscopy. Due to the low dielectric strength and the tendency to crystallize at elevated temperatures, a detailed shape analysis of the loss profile from the glass transition temperature Tg to approximately 1.2 Tg is not available for the neat glass former. Assessing the origin of the different temperature dependencies of translational and rotational motions in supercooled liquids and its possible connection to heterogeneity requires this knowledge regarding the possible changes in the relaxation-time distribution across the 100 s-100 ns relaxation-time range. This note provides this information for o-terphenyl on the basis of a master curve representation: time-temperature superposition applies with a constant stretching exponent of beta=0.5 in the range of interest.