PbBr2-PbF2-P2O5玻璃的结构研究

采用红外光谱（IR）和X射线光电子能谱（XPS）等方法研究了PbBr2-PbF2-P2O5系铅卤磷酸盐玻璃的结构。结果表明，Pb^2 离子在玻璃中起着网络修饰阳离子和网络形成体的双重作用。当P2O5含量为60mol%时，Pb^2 离子主要是作为网络修饰体；当P2O5含量降低到50mol%时，一部分Pb^2 离子能够进入玻璃网络形成PbO4]四面体或P－O－Pb键。Br^-和F^-离子达到一定浓度时就会进入玻璃网络，形成PO4-nXn](X=Br或F，n=0-4)四面体使磷酸盐链长变短。玻璃中P2O5的含量不变时P－O－P键的比例也基本保持不变；当P2O5的含量降低时，P－O－P键和P－O^-键的含量都减少，P－O－Pb键的含量则明显增加。

Structure Studies of PbBr2-PbF2-P2O5 Glasses

Glasses in the system of PbBr2-PbF2-P205 have low melting temperature, good water durability and good optical properties, which can serve as the host materials of organic-doped scintillator. In the present paper, the structure of PbBr2-PbF2-P205 glasses was characterised by Fourier transfer infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Results show that lead ions play dual roles, network former and network modifier, in the structure of PbBr2-PbF2-P2O5 glasses. When P2O5 content is 60mol%, most of Pb2+ ions act as network modifier. When P2O5 content decreases to 50mol% and even 40mol%, some Pb2+ ions could enter glass network and form Pb04] tetrahedron or P-O-Pb linkage with decreasing P20s content, while other Pb2+ ions still act as network modifier. The length of phosphate chains decreases with decreasing P2O5 content. Both Br-and F- ions could enter glass network and form PO4-nXn](X=Br or F, n = 0-4) tetrahedron when they reach certain content, breaking P04J tetrahedron and decreasing the length of phosphate chains. The P-O-P linkages content keep unchanged with the same P2O5 content. Decreasing P2O5 content and increasing lead halide content lead to the formation of P-O-Pb linkage through the delocalization of P=O and P-O-bonds.