Fluorescence spectroscopical investigation of the gelation of sterical stabilised titanium dioxide sols

The gelation of TiO2-sols, prepared by sol-gel process, can be monitored by adding polyethylene glycol as polymer (sterical stabilisation). The formin g: of the inorganic TiO2 network was examined by using the microprobe techn ique. Pyrene was doped in TiO2-sols and its characteristic fluorescence spe ctroscopic changes were investigated during the gelation. The vibrational f ine structure of its emission spectrum changes and the ratio I-3/I-1 was de termined and compared with homogenous solvents. By pulse fluorimetric measu rements two different lifetimes of pyrene in TiO2-sols were found.