Preparation of La2O3-TiO2-SiO2 Inorganic-Organic Hybrid Materials and Their Optical Properties

Inorganic-organic hybrid materials in La₂O₃-TiO₂-SiO₂ system were prepared from La(NO₃)₃, titanium tetraisopropoxide, and silicon alkoxides. Ternary transparent materials prepared from glycidyloxypropyltrimethoxysilane (GPTS) were obtained in a wide composition region (La₂O₃ 50 mol%, TiO₂ 40 mol%). Hybrid materials prepared using methyltrimethoxysilane (MTMS) at MTMS/TMOS = 1 were transparent in the composition of La₂O₃ 30 mol% and TiO₂ 25 mol%. La(NO₃)₃ crystallines or TiO₂ small particles were precipitated in translucent materials. La₂O₃ content strongly affected the bulk density compared with TiO₂ content. Absorption edge of the hybrid materials was shifted to longer wavelength as TiO₂ and La₂O₃ contents increased. Partial coefficient of refractive index for the three metal oxides increased in the order SiO₂ < TiO₂ < La₂O₃ for both hybrid materials.