The high refractive index La₂O₃–TiO₂–Nb₂O₅ glasses were prepared by containerless processing, and the glass-forming region was determined. The refractive index showed the range from 2.20 to 2.32, and the values were much higher than those of most optical glasses. The completely miscible 30LaO_3/2–(70−x)TiO₂–xNbO_5/2 (0 ≤ x ≤70) system was fabricated to study the compositional dependence of refractive index and optical transmittance. The crucial determinants of the refractive index of oxide glasses, oxygen molar volume, and electronic polarizability of oxygen ions were calculated. The principle of additivity of glass properties was suitable for the calculation of refractive index between glass and compositional oxides. All the glasses were colorless and transparent in the visible to 6.5 μm middle infrared (MIR) region. These results are useful for designing new optical glasses with high refractive index and low wavelength dispersion in wide optical window.

中文翻译：

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高折射率La2O3-TiO2-Nb2O5玻璃的光学性质，热稳定性和形成区域

通过无容器加工制备高折射率La ₂ O ₃ -TiO ₂ -Nb ₂ O ₅玻璃，并确定玻璃形成区域。折射率显示范围为2.20至2.32，并且该值比大多数光学眼镜的折射率值高得多。完全可混溶的30LaO _3/2 –（70− x）TiO ₂ – x NbO _5/2（  0≤x ≤70）系统用于研究折射率和透光率的成分依赖性。计算了氧化物玻璃的折射率，氧摩尔量和氧离子的电子极化率的关键决定因素。玻璃性质的加和原理适用于计算玻璃与组成氧化物之间的折射率。所有玻璃在可见到6.5μm中红外（MIR）区域均为无色透明。这些结果对于设计在宽光学窗口中具有高折射率和低波长色散的新型光学玻璃很有用。