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

低声子能量光学功能氧化物玻璃的独特结构弛豫机制

基本信息

批准号：
10650822
负责人：
KOMATSU Takayuki
金额：
$ 2.3万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650822/
关键词：
Tellurite glass Bismuth glass low phonon energy Glass transition Heat capacity Enthalpy relaxation Fragility Structural relaxation 構造暖和

项目摘要

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.

本研究的目的是通过测量玻璃转变区的粘度、热容和维氏硬度，阐明光学功能TeO_（22）O_（23）结果表明：1）R_（22）O_（20）O_（22（R=Li，Na，K，M=Mg，Ba，Zn）随着氧化物之间的组合而增加，显示出大的不同光学碱度（如K_（22）O_（20）O_（22）O_这意味着在这些玻璃中容易发生网络结构的破坏和网络单元之间的重新排列。这一特征表现在玻璃转变时维氏硬度的快速降低。3）TeO_（12）D_22_（12）D_2基玻璃的焓弛豫激活能为900 ~ 1250 kJ/mol，与硅酸盐玻璃相比大得多，粘流激活能为500 ~ 750 kJ/mol，脆性值约为60。在TeO双金属D22双金属D2-和Bi双金属D22双金属D2 O双金属D23双金属D2-基中清楚地观察到焓弛豫和粘性流之间的解耦（例如Bi系玻璃D22系玻璃D20系玻璃D23系玻璃D2-B系玻璃D22系玻璃D20系玻璃D23系玻璃D2）。4）TeO系玻璃D22系玻璃D2-和Bi系玻璃D22系玻璃D20系玻璃D23系玻璃D2-均属于易碎玻璃类别-形成系统。5）这两种系统在玻璃化转变时都显示出独特的结构弛豫，但本研究表明，可以制造具有高技术应用潜力的玻璃。