Glass transition of associated solvents studied by fluorescence measurement of doped chromophores

Abstract

The fluorescence lifetime of a triphenylmethane dye, malachite green, doped in three glass-forming associated solvents, 1-propanol, propylene glycol, and glycerol, was measured in a wide temperature range. For each sample three temperature regimes were found in the temperature dependence of the nonradiative relaxation time of malachite green. The lower crossover temperature corresponds to the calorimetric glass transition temperature, and the higher one, 30--50 K above the lower one, is attributed to the critical temperature that is predicted by mode-coupling theory. \textcopyright{} 1996 The American Physical Society.