Three laser dyes (perylene orange, perylene red and pyrromethene 567) were dispersed in TEOS-, TEOS/GPTMS-, MTES- and VTES-gel glasses, respectively. The surroundings and fluorescence photostability of the dyes in gel glasses were studied. Due to the formation of a hydrogen bond between the dye and the residual Si-OH attached on the surface of the cages and pores, spectral red shifts of perylene orange at 10 K in TEOS- and TEOS/GPTMS-gel glasses with respect to that in MTES- and VTES-gel glasses were observed. Perylene dyes are more likely to trap in the cages of MTES- and VTES-gel glasses and show high-fluorescence photostability, while ionic and polar pyrromethene 567 tend to appear in the polar pores of gel glasses, which leave pyrromethene 567 vulnerable to photochemical reactions with singlet oxygen and low-fluorescence photostability. (C) 2002 Elsevier Science B.V. All rights reserved.