Solvent effect on fluorescence lifetimes at swollen glassy–rubber interphase domains in blendlike particles

Abstract

AbstractFluorescence of naphthalene (N) labeled to poly(methyl metracrylate) (PMMA) particles sterically stabilized by polyisobutylene (PIB) was studied by transient fluorescene method in iso–octane, hexadecane, and in powder from. When samples of dispersions are annealed above 60°C, their room temperature lifetimes increase, and when powder samples are so annealed, lifetimes decrease. Self‐quenching effects among N*/N pairs were eliminated to isolate unimolecular lifetimes. Low‐frequency intramolecular vibrations are found responsible for the temperature dependence of nonradiative transition of excited N molecules. Corresponding activation energies are measured and found to be between 2300 and 1100 cal/mol. Solvent effects on these activation energies are discussed. © 1995 John Wiley & Sons, Inc.