The europium dibenzolymethide has been embedded with high concentration in a polystyrene matrix using spin-coating deposition. We have investigated the temporal stability of the film in measuring simultaneously the intensity I and decay time tau of fluorescence and the sample transmittance T at the excitation wavelength. The low bleaching efficiency is measured in the order of 10(-4). During the photobleaching process, it appears that there are some non-monotonous fluctuations on tau and T, whereas I decreases continuously, depending on the film thickness d and the chromophore concentration N-0. In addition, we show that these films can be used to probe a metallic surface by means of the quenching effect.