Abstract

TALHAVINI, M.  and  ATVARS, T. D. Z.. Phosphorescence lifetime in polymer relaxation studies: phase resolution method. Quím. Nova [online]. 1998, vol.21, n.3, pp. 332-336. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40421998000300015.

We describe in this work a simple experimental set up to perform time dependent luminescence experiments in time scales from mili-seconds to seconds, based on the phase resolution of the emission signal. This system is composed by modulation of a continuous light source with an external chopper controlled by a lock-in amplifier. We exemplified the utility of the system in studies of phosphorecence emission using benzophenone dissolved in polystyrene and since the phosphorescence intensity and lifetime are temperature-dependent processes, we also studied polymer relaxation processes in the temperature range from 20 to 400K. A software that drives the spectrofluorimeter and controls both the cryosystem and the lock-in amplifier was developed.

Keywords : phase resolution lifetime determinations; benzophenone; polymer relaxation processes.