Mechanism of Unique Structural Relaxation of Optical Functional Oxide Glasses with Low Phonon Energy

The purpose of this study is to clarify the mManagement ism of unique structural relaxation of optical functional TeO-D2-and Bi-D22-D2O-D23-based glasses with low phonon energies through measurements of viscosity， heat capacity and Vickers hardness in the glass transition region。The following results were obtained.1） the thermal stability against crystalliization in R-D22-MO-TeO R-D22玻璃（R=Li，Na， K， M=Mg， Ba， Zn）氧化物之间的组合物增加了不同的光学基础物（e.g. K-D22 G2O-MgO， Li G22 G20-BaO）。2） the heat capacity changes at the glass transition in K-D22 G20-MgO-TeO G22 G2glasses are extremely large，I.e. ΔC D2P D2A= 45 J/molK，它的意思是，网络结构和网络之间的联系在这些玻璃上很容易被捕获。这一特征出现在Vickers在玻璃过渡中的硬度迅速下降的情况下。3）TeO D22基于D2的玻璃为900 - 1250千焦/莫的激活能量，其中许多与硅玻璃比较较大，而那些模糊的流量为500 - 750千焦/摩尔，在60左右赋予了脆弱性值。The decoupling between enthalpy relaxation and viscous flow is clearly observed in both TeO-D22-and Bi-D22-D2O-D23-based（such as Bi·D22·D23·D2-B·D22·D23·D2） glasses.4） both TeO·D22·D2-and Bi·D22·D23·D2-based glasses belong to the category of fragile glass-成形系统.5）两个系统在玻璃过渡中展示独特的结构放松，但目前的研究演示，因为它是有可能制造玻璃具有高潜力的技术应用。

The purpose of this study is to clarify the mechanism of unique structural relaxation of optical functional TeOィイD22ィエD2- and BiィイD22ィエD2OィイD23ィエD2-based glasses with low phonon energies through measurements of viscosity, heat capacity and Vickers hardness in the glass transition region. The following results were obtained.1) the thermal stability against crystallization in RィイD22ィエD20-MO-TeOィイD22ィエD2 glasses (R=Li,Na, K, M=Mg, Ba, Zn) increases with the combination between oxides showing large different optical basicities ( e.g. KィイD22ィエD2O-MgO, LiィイD22ィエD20-BaO).2) the heat capacity changes at the glass transition in KィイD22ィエD20-MgO-TeOィイD22ィエD2 glasses are extremely large, I.e. ΔCィイD2PィエD2A=45J/molK, meaning that the breaking of the network structure and rearrangements among network units occur easily in these glasses. This feature is appeared in a rapid decrease of Vickers hardness at the glass transition.3) the activation energies for enthalpy relaxation in TeOィイD22ィエD2-based glasses are 900〜1250kJ/mo, which are much large compared with silicate glasses, and those for viscous flow are 500〜750kJ/mol, giving the fragility values of around 60. The decoupling between enthalpy relaxation and viscous flow is clearly observed in both TeOィイD22ィエD2- and BiィイD22ィエD2OィイD23ィエD2-based (such as BiィイD22ィエD20ィイD23ィエD2-BィイD22ィエD20ィイD23ィエD2) glasses.4) both TeOィイD22ィエD2- and BiィイD22ィエD2OィイD23ィエD2-based glasses belong to the category of fragile glass-forming systems.5) both systems show a unique structural relaxation at the glass transition, but the present study demonstrates that it is possible to fabricate glasses having high potential for technical applications.