การประชุมวิชาการระดับชาติ ครั้งที่ 16
มหาวิทยาลัยราชภัฏนครปฐม

This study investigates the impact of manganese ions on the decolorization effect of glass samples produced from rice husk ash with varying concentrations of manganese ions denoted by xMnO₂ (ranging from 0.0 to 0.5 mol%). The chemical formula of glass composition is represented as (55-x) SiO₂: 25B₂O₃: 10Na₂O: 10CaO: xMnO₂. The elemental composition analysis of rice husk ash reveals that it mainly composed of 97%, silicon dioxide by weight, suggesting its potential as a substitute for silicon dioxide or sand in glass production. This study further explored the physical and optical properties of the glasses. With increasing MnO₂ concentration, there is a corresponding increase in density, molar volume and refractive index. Absorption spectra of MnO₂ are not observable due to the presence of Fe₂O₃ in the rice husk ash. However, doping MnO₂ into the glass samples induces an oxidation-reduction reaction, leading to reduced coloration of the glasses. Furthermore, color analysis using the CIE L^*a^*b^* color space reveals that the glass sample doped with 0.2 mol% of MnO₂ has virtually colorless (L^* = 80.1077, a^* = - 0.5116, b^* = 2.8436). This suggests potential for the development of various colored glasses utilizing this sample.