G-2 Elastic anomaly of glass transitions in Lithium Silicate(Photoacoustics, Acousto-optics)

概要

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The temperature variation and composition dependence of elastic properties and fast relaxation process have been studied in lithium silicate glasses with different J =0.3, 0.4, 0.5, 0.6 and 1.0 by the micro-Brillouin scattering technique. The room temperature longitudinal elastic modulus increased significantly with increasing Li concentration indicating the additional cross-linking in network structure. the presence of the lithium does not break up the network, the part of the produced non-bridging oxygens brought in by the lithium oxides and result in additional cross-linking between network units. For all components (J=0.3〜1.0), the rigidity decrease with increasing temperature. The rate of decrease becomes significantly stronger above the glass transition temperature. This is due to the disruption in network bonds, causing the rigidity of the melt structures to decrease with increasing temperature. The network degradation is more rapid with increasing lithium oxide concentration. The overall increase in full width half maximum of Brillouin peak reflects the thermally activated mechanism at the GHz frequency range, the transport of momentum responsible for viscous dissipation increase with temperature.
超音波エレクトロニクスの基礎と応用に関するシンポジウム運営委員会の論文
2004-10-27