LONG RANGE INTRAMOLECULAR EXCIMERS.

A method was recently proposed to calculated for any polymer having excimer emission, the percentage of intra molecular excimers formed by (a) preformed ground state dimers, (b) rotation during the excited state lifetime or (c) long range intracoil interactions. The method is based on several hypothesis. It is assumed that at constant temperature and polymer molecular weight, the contribution of each mechanism to the total excimer emission is additive and depend only on one variable: (a) depend only on polymer configuration or tacticity, (b) depend only on solvent viscosity and (c) depend only on intracoil segmental density. The authors test the method with polymers in which mechanisms (a) and (b) are sterically suppressed and in this way we can consider the variables determining the formation of long range excimers by mechanism (c). We have selected poly-acenaphthylene (PAN), polyindene (PI) and poly(1-naphthylmethacrylate) (P1NMA).