We present here some results of the research of photostability and spectral and lasing properties of active laser media based on organic dyes like rhodamine 6G and coumarin 7 in the methylmethacrylate with methacrylic acid copolymer, modified by a number of urea derivatives. The photostabilizing effect of these compounds revealed as well as its impact on the kinetic and resulting characteristics of the copolymerization process were studied.