LIGHT-SCATTERING AND TIME-RESOLVED FLUORESCENCE STUDY OF THE BEHAVIOROF A FLUORESCENTLY TAGGED POLY(METHYL METHACRYLATE) SAMPLE IN POLAR ORGANIC-SOLVENTS

Steady-state and time-resolved fluorometry, quasielastic light scatter ing, and viscometry were used to study solution behavior of fluorescen tly tagged poly(methyl methacrylate) (PMMA) in binary mixtures of 1,4- dioxane with either 2,2,3,3-tetrafluoropropanol (TFP) or methanol. In 1,4-dioxane/TFP mixtures, which are good solvents for PMMA, an intermo lecular association occurs. It was shown by time-resolved fluorometric measurements that the unusual behavior of PMMA in good solvent mixtur es is due to association of nonpolar fluorophores in a polar medium. A ssociation processes were not detected in systems containing a virtual ly identical, but nontagged PMMA sample in the same solvent mixtures. In mixed solvents of 1,4-dioxane/methanol, association of the tagged ( as well as nontagged) sample does not take place.