Abstract
"Red-edge effect" was measured for trehalose glass, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), and 1-propanol (PrOH) at different temperatures utilizing coumarin 153 (C153) as a fluorescent probe molecule. The featureless broad fluorescence spectrum of C153 in PrOH at 200 K exhibited no excitation dependence while that with vibrational structure at 81 K exhibited clear red-edge effect at frequencies lower than 22,500 cm^<-1>. The fluorescence of C153 in trehalose exhibited weak red-edge effect even at 298 K and it became more distinctive at lower temperatures. However, the vibrational structure was not clear and the spectral feature was closer to those in PMMA and PVA. Solvent motion in polymers seems to be more mobile compared to PrOH glass due to their larger free volume and the mobility in trehalose glass seems to lie between them.
