Physical aging in glassy o-terphenyl monitored by probe rotation.
The physical aging of o-terphenyl was studied through its influence on the rotation rate of probe molecules (1-naphthylazomethoxybenzene) over a temperature range from 231 (T(g)-12 K) to 238.5 K (T(g)-4.5 K). An optical anisotropy decay technique was used to monitor the molecule rotation. The rotation slows down strongly as the aging proceeds. It was shown that the aging dynamics is spatially heterogeneous. The anisotropy decay is well described under the following assumptions: (i) the temperature and structure dependencies of the relaxation time follow the Scherer-Hodge equation and (ii) the time of rotation is proportional to the time of structural relaxation.
Syutkin
V M
VM
Institute of Chemical Kinetics and Combustion, Novosibirsk 630090, Russian Federation. syutkin@kinetics.nsc.ru
Grebenkin
S Yu
SY