Changes in Optical Transmittance of Ultrafine-particle doped Glass by Nitrogen Oxide Gas

Ultrafine-particle doped glass nanocomposites that show changes in optical property by gas atmosphere were developed by using a sol-gel process. The nanocomposites consist of silica glass matrix, functional ultrafine-particles and micropores. Transition metal oxides or noble metals were used as the functional ultrafine-particles in this study. Diameters of doped particles were confirmed to be in the order of nano-meter by X-ray diffractometry and transmission electron microscopy. When the nanocomposites were exposed to NO gas flow (0.75 vol%) at 350 ��, the optical transmittance of the Au-doped glass nanocomposite largely decreased at 400 nm, while that of the Fe oxide- or the Co oxide- doped glass nanocomposites largely increased at 600 nm.