Mutual influences of sol-gel matrices and dopants on the materials opticalproperties

The optical properties of doped sol-gel derived materials were studied. Two types of materials were examined; thin films doped with titanium dioxide a nd bulks doped with pH indicators: Bromothymol Blue and Nile Red. Different amounts of TiO2 tin concentrations: 20, 40, 60 and 80 mol%) were entrapped into the silica sol-gel thin films. The refractive indices of the films we re measured. A linear increase of refractive index with increasing addition of TiO2 was observed. Bromothymol Blue and Nile Red pH indicators were ent rapped into the sol-gel bulks. Two methods of dye immobilization were used. In the first method, indicators were mixed with liquid hydrolyzate used fo r bulk preparation. In the second one, the dried sol-gel bulks were impregn ated with liquid dye solutions. The absorption spectra in visible range wer e examined for dyes in solutions and sol-gel bulks. Changes in absorption s pectra were observed depending on the way of dopant entrapment.