Femtosecond fluorescence dynamics and molecular interactions in a water-soluble nonlinear optical polymeric dye
نویسندگان
چکیده
Ž . The excited state dynamics of a water-soluble polymeric dye poly S-119 was investigated using femtosecond time-reŽ . solved fluorescence upconversion. Multi-exponential relaxation of fluorescence was observed for poly S-119 in picosecond and sub-picosecond time ranges. The azo-chromophore of the functionalized polymeric dye Sunset Yellow was used as a model compound for detailed investigations of intermolecular interactions. Excited state decay of this azo-dye can be described by a two-exponential decay law with time-constants of ;0.48 ps and 1 ps. Fluorescence anisotropy decay was investigated for both systems. The difference in excited state dynamics between the polymeric dye and the azo-chromophore is explained in terms of inter-molecular interactions resulting in intra-chain aggregate formation. q 2000 Elsevier Science B.V. All rights reserved.
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