Niobium alkali germanate glasses were synthesized by the melt-quenching technique. The ternary system (90-x)GeO₂–xNb₂O₅–10K₂O forms homogeneous glasses with x ranging from 0 to 20 mol%. Samples were investigated by DSC and XRD analysis, FTIR and Raman spectroscopy, and optical absorption. Structural and physical features are discussed in terms of Nb₂O₅ content. The niobium content increase in the glass network strongly modifies the thermal, structural and optical properties of alkali germanate glasses. DSC, Raman and FTIR analysis suggest niobium addition promotes NbO₆ groups insertion close to GeO₄ units of the glass network. XRD analysis also pointed out that samples containing high niobium oxide contents exhibit preferential niobium oxide-rich phase after crystallization after heat treatment, which is similar to orthorhombic Nb₂O₅. Absorption spectra revealed high transmission range between 400 nm to 6.2 μm, added to a considerably decreased hydroxyl group content as the addition of niobium in the alkali germanate network. The niobium oxide-rich phase crystallization process was studied and activation energy was determined, as well as nucleation and crystal growth temperatures and time for obtaining transparent glass-ceramics.

中文翻译：

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德国玻璃中的氧化铌含量高：热，结构和光学特性

通过熔融淬火技术合成了碱金属锗酸铌玻璃。三元体系（90- x）GeO ₂ – x Nb ₂ O ₅ –10K ₂ O形成均质玻璃，x的范围为0至20 mol％。通过DSC和XRD分析，FTIR和拉曼光谱以及光吸收对样品进行了研究。根据Nb ₂ O ₅含量讨论了结构和物理特征。玻璃网络中铌含量的增加极大地改变了碱式锗酸盐玻璃的热，结构和光学性能。DSC，拉曼光谱和FTIR分析表明，添加铌可促进NbO ₆基团接近GeO的插入玻璃网络的_4个单位。XRD分析还指出，高铌氧化物含量的样品在热处理后结晶后表现出优先的富铌氧化物相，这与正交晶Nb ₂ O ₅相似。吸收光谱显示在400 nm至6.2μm之间的高透射范围，随着碱锗酸盐网络中铌的添加，羟基含量大大降低。研究了富铌氧化物相的结晶过程，确定了活化能，以及成核和晶体生长温度以及获得透明玻璃陶瓷的时间。