抄録
Azobenzene was dispersed in sol-gel silica derived from tetramethoxysilane. Absorption spectra of azobenzene in silica showed a peak at 320 nm, showing a trans form of azobenzene. The 320 nm peak decreased by UV light irradiation, and generation of the absorption peak at 250 nm was observed. It is suggested that a structure of azobenzene changes from ″trans″ to ″cis″. Recovery of the 320 nm peak and disappearance of the 250 nm peak were observed when visible light was irradiated for the gels without adding HCl, showing the regeneration of trans-azobenzene from cis-azobenzene. A similar photochromic property was observed for sols containing HCl. However, recovery of the 320 nm peak and disappearance of the 250 nm peak were not observed for the gels containing HCl after visible light irradiation. The effects of matrices on photochromism will be discussed.
