The absorption spectra and fluorescence spectra of Rhodamine 6G were measured in mixed solvents of benzene and MeOH. As the concentration of MeOH in the solution increases, fluorescence intensity and optical d. increase too, although the concentration of Rhodamine 6G is kept constant For exclusion the possible increase in fluorescence intensity contributed by the increase of quantum yield in MeOH, decay time of Rhodamine 6G in solution with different compns. of benzene and MeOH were measured and the results show that the decay life times are only slightly increased which can not compensate the increase in fluorescence intensity. The reasonable explanation is that as the concentration of MeOH in the solution increases, the dielec. constant of the solution increases so the dissociate constant becomes larger and larger. The increases of optical d. and fluorescence intensity are contributed by the increase of ion of Rhodamine 6G.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, QUANTUM YIELDS, LASER MATERIAL, RHODAMINE, FLUOROSPECTROPHOTOMETRY, FLUORSCENCE DECAY, FLUORESENCE DYES