锂铝硅磷酸盐玻璃的紫外透射性能与玻璃结构

Ultra-Violet Transmission and Structure of Lithium Aluminum Silicate-Phosphate Glasses

石英玻璃因为其紫外(UV)透射性能较好,常被用来作为紫外探测器的窗口材料。但是它的热膨胀系数较小,如果和其他材料直接封接,就会产生内应力,从而对材料造成损伤。为此,以SiO2、P2O5、Al2O3、Li2O作为组分,制备紫外透射性能好(波长200nm处,最高达到56%)、热膨胀系数高,同时具有较好稳定性的透紫外玻璃。利用固体核磁共振(MAS-NMR)、红外光谱(FTIR)对玻璃的局部结构进行表征和研究。结果表明,玻璃中的硅原子处于4配位状态;磷原子开始是3配位态,随着Al2O3含量的增加,磷氧四面体中出现了一个非桥氧键P-O…Li,而铝原子的平均配位数不断减少;Si-O-P键、Si-O-Al键以及P-O-Al键的出现,表明三个组分之间相互交联,形成一个整体;Si-O-P键越少,Si-O-Si键越多,紫外透射率越高。

Silica glasses are often used as the window material of ultra-violet （UV） detector due to having a high UV transmittance. However, this glass is not allowed to connect with other materials directly for its lower thermal expansion coefficient, otherwise, the innerstress can damage the materials. Therefore, using SiO2, P2O5, Al2O3, Li2O as the components, the optical glasses with the high UV transmittance （the maximum up to 56% at 200 nm wavelength）, high thermal expansion coefficient and good stability is prepared. The local structure of glasses is studied by magic angle spinning nuclear magnetic resonance （MAS-NMR） and Fourier transform infrared spectroscopy （FTIR）. The results show that Si atoms in the glasses are located in the 4-coordinated states and phosphate groups are similar with ultraphosphate groups Q3 originally. And with the Al2O3 content increased, there is a non-bridge oxygen （P-O…Li）. At the same time, the average of Al coordination number gradually reduces. The formation of Si-O-P, Si-O-Al and P-O-Al bridge oxygens indicates that the cross-linking among the three components is caused to form a three-dimensional network structure. Moreover, the UV transmittance can be improved when increasing Si-O-Si bonds and decreasing Si-O-P bonds.