Isomerization and optical bistability of DR1 doped organic–inorganic sol–gel thin film

• Sol–gel hybrid films doped with DR1 molecules based on TiO2/ormosil have been successfully prepared.
• Thermal stable working temperature range was obtained under Tg of as-prepared film.
• A better OB-gain was achieved in the as-prepared films than that of the PMMA/DR1 film at 532 nm.
• Increasing titanium content in the TiO2/ormosils hybrid system leads to better OB-gain.

To investigate the isomerization process of the disperse red 1 (DR1) doped TiO2/ormosil thin film, both the photo-isomerization and the thermal isomerization of the thin films were observed as a change of the absorption spectrum. Under a real-time heat treatment, the change of the linear refractive index shows a thermal stable working temperature range below Tg. The optical bistability (OB) effect of the DR1 doped thin films based on different matrices was studied and measured at a wavelength of 532 nm. Results indicate that the TiO2/ormosils based thin film presents a better OB-gain than that of the poly (methyl methacrylate) (PMMA) based thin film due to its more rigid network structure. Moreover, it is also noted that higher titanium content is helpful for enhancing the OB-gain of the as-prepared hybrid thin films.