The fluorescence spectra of alkyl b-naphthoates with various chain lengths (An) in DMSO-H2O and ethylene glycol-H2O mixtures were studied. The b-naphthoates with short chain show monomer fluorescence only in both solvent mixtures, while the fluorescence spectra of long chain alkyl b-naphthoates are dominated by excimer emission. The addition of long chain hydrocarbon and amylose resulted in the reduction of excimer emission and the enhancement of monomer fluorescence. All these experimental results support intermol. aggregation of long chain alkyl b-naphthoates in poor solvents. The kinetic parameters of formation and dissociation of excimer as well as fluorescence polarization in aggregates were measured.

Key words: PHOTOCHEMICAL REACTION, ETHANEDIOL, CARBOXYLIC ACID ESTER, DMSO, PHASE TRANSFORMATION, ENTHALPY, QUENCHING EFFECTS, ACTIVATION ENERGY, REACTION RATE CONSTANT, HYDROPHOBIC PROPERTIES