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首页> 外文期刊>Journal of Materials Science >STRUCTURAL INVESTIGATIONS OF PHOSPHATE GLASSES - A DETAILED INFRARED STUDY OF THE X(PBO)-(1-X)P2O5 VITREOUS SYSTEM [Review]
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STRUCTURAL INVESTIGATIONS OF PHOSPHATE GLASSES - A DETAILED INFRARED STUDY OF THE X(PBO)-(1-X)P2O5 VITREOUS SYSTEM [Review]

机译：磷酸盐玻璃的结构研究-X（PBO）-（1-X）P2O5玻璃体系统的详细红外研究[综述]

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摘要

The results and detailed discussion of an extensive experimental study of infrared spectra of the x(PbO)-(1 - x) P2O5 vitreous system (x = 0.3-0.75) together with a brief review of infrared spectra of phosphate compounds, are presented. Theoretical models employed in the interpretation of infrared spectra of glasses have been reviewed. The frequency ranges of various infrared bands belonging to PO43- and P2O74-, observed in different phosphate compounds, are discussed. The glassy and quenched samples were prepared from PbO and NH4H2PO4 by the rapid quenching technique. The infrared spectra of the constituents of the system, PbO and P2O5, in their polycrystalline and glassy forms, have been discussed. The intensity and wavenumbers of the infrared bands around 1600 and 3300 cm(-1), assigned to the bending and stretching modes in H2O trapped by the hygroscopic glasses, have been followed for different compositions with x < 0.5. The changes observed in these infrared bands established the role of water as an additional glass modifier. The intensity and frequency variations of the infrared bands have been followed th rough all the com positions for characteristic phosphate group frequencies including P=O, P-O-P stretching and bending modes and P-O bending mode. The results clearly suggest that the x(PbO)-(1 - x) P2O5 system undergoes gradual structural changes from metaphosphate (x = 0.5), to pyrophosphate (x = 0.66) and to orthophosphate (x = 0.75). The continuing presence of the infrared band, in varying intensity, in the region 1200-1280 cm(-1) attributed to P=O, suggests that the glass-forming ability of the binary system is extendable at least up to x = 0.66 composition, and that no complete rupture of P=O bond by Pb2+ takes place. The ionic character of the phosphate groups, P-O-(-), PO43- is well revealed by significant changes with the PbO content in the spectral features of the infrared bands around 1120 and 980 cm(-1) respectively. The maximum intensity of the P-O-(-) band at 1120 cm(-1) for 55 mol% PbO suggests a partial breakdown of the covalent vitreous network of the phosphates and formation of a crystalline phase consisting of ionic groups PO43-, P2O62- and P2O74- for PbO greater than 55 mol%. The observed pattern of variation in the intensity of the infrared bands in the 940-1080 cm(-1) region attributed to the nu(3)-mode in PO43-, suggests a gradual transformation of PO43- units to PO3- groups in lead meta-phosphate glass and then their restoration to PO3,- groups of pyro- and ortho-phosphate quenched samples. The results indicate a gradual decrease in the number of bridging oxygens and increase in the resonance behaviour of non-bridging oxygens as the mole percentage of metal oxide (PbO) increases in the glass. The infrared spectra of several binary phosphate glasses have been reviewed in the context of the study of effect of the cation on the infrared spectra. It is found that the influence of the cation on the infrared spectra of phosphate glasses does not show any striking regularity. Theoretical calculations of these ban d frequencies were found to agree well only in the case of pure stretching (P=O and O - H) vibrations and pure bending (P-O-P and O-H) vibrations. The disagreement in the case of P-O-(-), P-O-H and other modes of P-O-P groups, has been attributed to the mixed nature of modes occurring in glasses. The changes in the positions of the characteristic bands and their relative intensities are strongly dependent on the structural units and PbO content in the phosphate glasses and the results emphasize the role of PbO as a network modifier. [References: 84]
机译：介绍了x（PbO）-（1-x）P2O5玻璃体系统（x = 0.3-0.75）的红外光谱的广泛实验研究的结果和详细讨论，并简要回顾了磷酸盐化合物的红外光谱。回顾了用于解释玻璃的红外光谱的理论模型。讨论了在不同的磷酸盐化合物中观察到的属于PO43-和P2O74-的各种红外波段的频率范围。通过快速淬灭技术，从PbO和NH4H2PO4中制备了玻璃状和淬灭的样品。已经讨论了多晶和玻璃态体系的组成成分PbO和P2O5的红外光谱。对于x <0.5的不同成分，已遵循1600和3300 cm（-1）附近的红外带的强度和波数，这些红外带被分配给由吸湿玻璃捕获的H2O中的弯曲和拉伸模式。在这些红外波段中观察到的变化确立了水作为其他玻璃改性剂的作用。跟踪了红外波段的强度和频率变化，包括P = O，P-O-P拉伸和弯曲模式以及P-O弯曲模式在内的所有磷酸盐特征频率的所有位置。结果清楚地表明，x（PbO）-（1-x）P2O5系统经历了从偏磷酸盐（x = 0.5）到焦磷酸盐（x = 0.66）和正磷酸盐（x = 0.75）的逐渐结构变化。在1200-1280 cm（-1）区域中归因于P = O的红外光谱带，强度不断变化，表明该二元体系的玻璃形成能力至少可以扩展到x = 0.66 ，并且没有发生Pb2 +完全破坏P = O键的情况。磷酸根基团P-O-（-），PO43-的离子特性可以通过分别在1120和980 cm（-1）附近的红外波段的光谱特征中PbO含量的显着变化来很好地揭示。对于55摩尔％PbO，PO-（-）谱带在1120 cm（-1）处的最大强度表明磷酸盐的共价玻璃体网络部分分解，并形成由离子基团PO43-，P2O62-组成的结晶相PbO大于55 mol％时使用P2O74-。观察到的归因于PO43-中的nu（3）模式的940-1080 cm（-1）区域中的红外波段强度变化模式表明，铅中PO43-单元逐渐转变为PO3-基团偏磷酸盐玻璃，然后将其还原成焦磷酸和正磷酸盐淬火样品的PO3-基团。结果表明，随着玻璃中金属氧化物（PbO）摩尔百分比的增加，桥连氧的数量逐渐减少，非桥连氧的共振行为增加。在研究阳离子对红外光谱的影响的背景下，已经综述了几种二元磷酸盐玻璃的红外光谱。发现阳离子对磷酸盐玻璃的红外光谱的影响没有显示任何惊人的规律性。仅在纯拉伸（P = O和O-H）振动和纯弯曲（P-O-P和O-H）振动的情况下，发现这些禁能频率的理论计算结果非常吻合。在P-O-（-），P-O-H和其他P-O-P基团模式中，存在分歧的原因是玻璃中存在的模式混合性质。特征带的位置及其相对强度的变化在很大程度上取决于磷酸盐玻璃中的结构单元和PbO含量，结果强调了PbO作为网络改性剂的作用。 [参考：84]

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