抄録
By means of fluorescence correlation spectroscopy (FCS), a decay component faster than the translational diffusion of the fluorescent probe molecule was observed in highly concentrated aqueous solutions of saccharides. We concluded that the fast decay is due to the increased lifetime of the excited triplet (T_1) state of the probe molecule. The lifetime of T_1 state was too short to be observed by FCS in aquous solution, because of the quenching by oxygen molecules (O_2). With high concentration of saccharides, the quenching is reduced because the encounter of the O_2 molecule with the probe molecule is interrupted. Time-resolved transient absorption spectroscopy was carried out and it was confirmed that T_1 state lifetime lengthened in highly concentrated viscous saccharide solutions. It was concluded that either the concentration or translational diffusion rate of oxygen molecule are reduced.
