二元钾硅酸盐玻璃结构的Raman光谱分析

RAMAN SPECTROSCOPIC ANALYSIS FOR THE STRUCTURE OF BINARY POTASSIUM SILICATE GLASSES

用带空间分辨和累积时间分辨耦合系统的Raman光谱仪,测定了二元钾硅酸盐K2O·xSiO2玻璃及晶体的Raman光谱,比较并解释了随SiO2含量变化的微结构单元Raman振动模。结果表明:钾硅酸盐玻璃有多种微结构单元共存,并且随二氧化硅含量的增加,微结构逐步由硅氧四面体单体向二聚体、链状、层状和网络状转化。硅氧四面体对称伸缩振动区的主峰不对称性以及展宽主要是由于一系列具有不同微环境下的二级结构的变化造成的。微环境的不同是造成精细微结构单元和光谱表征差异的根本原因。Raman光谱的精细结构反映了微结构单元连接的复杂性,采用二级结构的概念有利于在更深层次和更大的空间范围内来认识硅酸盐玻璃微结构。

Raman spectra of series glasses and crystals of binary potassium silicate were measured by a newly constructed Raman spectrometer coupled with space and accumulated time resolved technique. Raman active vibration modes of microstructure units with changed SiO2 contents were compared and elucidated. Results show that the multi micro-structure units coexist in the potassium silicate glasses, and with the increase of SiO2 content, the micro-structures may transfer in sequence from silicon-oxygen tetrahedron monomer to dimmer, chain, sheet and network step by step. The asymmetric and broadening of Raman band around the main peak in symmetric stretching vibration region are mainly caused by the variant of secondary-structure in various microenvironments. The basic reason of the difference between delicate micro-structure units and spectral characteristics is the different microenvironments. The fine structure of Raman spectra is the reflection of the complexity of connectivity of the micro-structure units. The concept of secondary-structure will lead to a new delicate consideration and further research on the micro-structure of silicates glasses.