The DMANS (4-dimethylamino-4'-nitrostilbene) is a better one of fluorescence dyes. It has three characteristics: Short fluorescence lifetime

higher quantum efficiency and larger Stokes shift. The spectrum Stokes shift depends on the polarity and the flexibility of the polymer matrix.In order to prepare a fast red-emission plastic scintillators and a solar energy collector

we have studied that the fluorescence behaviour of the DMANS in the polystyrene and the flexible polystyrene. Absorption spectrum

fluorescence spectrum

fluorescence intensity and fluorescence lifetime of these samples have been measured. Results indicate that the polarity and the flexibility of polymer matrix influence the fluorescence behaviours of the DMANS. The mechanism of influorescence behaviour has been discussed also.