Relation between excimer formation in small probes and free-volume theory in polymer melts

Abstract Intramolecular excimer formation of meso-2,4-di( N -carbazolyl)pentane dissolved in different elastomers has been investigated. The intramolecular conformational change required for the excimer sampling process is shown to be controlled by the segmental motions of the polymer matrix involved in the glass transition phenomenon. The results show that, at a fixed frequency of the probe motion, the fractional free volume as well as the free volume per atomic group vary from one polymer to another.