Energy Transfer and Molecular Weight Effects on Polymer Luminescence

Abstract

Energy transfer in, and luminescence from polymers in dilute rigid glasses and solid polymer films are subjects of extensive current research. This interest stems partly from the vast differences in optical and electronic properties which polymers exhibit and their usefulness. A microscopic description of how electronic energy is transported and trapped and the various routes of dissipation is essential for understanding inhibition of photodegradation processes in polymers. This chapter will have the limited objectives of (a) reviewing the experimental evidence for intramolecular energy transfer in polymers as demonstrated initially by Fox and Cozzens (1), (b) summarizing experimental evidence for dependence of delayed fluorescence and phosphorescence on the molecular weight of the polymer, (c) developing a simple model which accounts for the enhancement of the delayed fluorescence with increasing degree of polymerization and its saturation for high molecular weight polymer, and (d) discussing the time dependence of polymer intramolecular excimer and monomer luminescence using the spectral function formalism for a one- dimensional transport model. The chapter is not intended to be exhaustive in its treatment but rather selective, illustrating the general concepts involved.