PHOTOPHYSICAL PROPERTIES OF 5 LASER-DYES (C120, C1, C102, C1F AND C153) IN HOMOGENEOUS, SURFACTANT AND MEMBRANE MEDIA

The absorption and fluorescence spectra of the title compounds have been investigated in solvents such as water, methanol and dioxan, in surfactants such as sodium dodecyl sulphate, cetyl trimethyl ammonium chloride and Triton X-100 and in a Nafion medium. The spectral shifts in each case are compared and related to the properties of the medium. In aqueous and surfactant media, the maximum red shift in the absorption is observed for C153 and the absorption increases in the order C120, C1, C102, C1F and C153. The fluorescence maxima also showed the same trend as the absorption shifts. Of the solvents, the least-polar solvent dioxan gave the maximum blue shift. In Triton X-100, the dyes registered the maximum blue shift. More or less the same trend is observed in both the absorption and the emission cases. In Nafion, C120 showed the maximum binding density of 3.58 x 10(-7) mol mg-1 and C1F showed the minimum binding density of 7.6 x 10(-8) mol mg-1. The spectra of the dyes in Nafion exhibited unusual broadening both for absorption and for emission owing to the immobilization of the dyes in this medium of restricted geometry.