若干硫系玻璃黏度变化速率的结构起源探索

用熔融淬冷法制备Ge₃₃As₁₂Se₅₅、Ge₂₂As₂₀Se₅₈、Ge₁₀As₄₀Se₅₀、As₄₀Se₆₀、Se硫系玻璃,采用流变仪测试样品黏弹状态的黏度,计算各样品黏度的Vogel-Fulcher-Tammann 方程和黏度变化速率(即料性)。结合拉曼光谱,根据玻璃微观结构对料性的影响规律进行系统分析。发现随着Ge_xAs_ySe_100-x-y硫系玻璃中Ge、As含量的增加,玻璃黏度随温度的变化速率先降低再升高,料性先变长后变短。在平均配位数=2~2.6时,随着平均配位数的增大,组成玻璃的原子之间的平均键能和网络结构稳定性逐渐变大,黏度变化速率降低,料性变长;在=2.6~2.78时,随着网络结构中As-As/Ge-Ge缺陷键的出现,玻璃网络结构的稳定性降低,玻璃黏度的变化速率加快,料性变短。

Structural Origin of Change Rate in Viscosity for Several Chalcogenide Glasses

Ge₃₃As₁₂Se₅₅, Ge₂₂As₂₀Se₅₈, Ge₁₀As₄₀Se₅₀, As₄₀Se₆₀, and Se chalcogenide glasses were prepared by the melt-quenching technique. The viscosities of these chalcogenide glasses were measured by a rheometer. Based on these data, the corresponding Vogel-Fulcher-Tammann equationsand change rate in viscosity were obtained. Based on the Raman spectra, the structural characteristics of these glasses were analyzed systematically. With the increase of Ge and As content in Ge_xAs_ySe_100-x-y chalcogenide glasses, the change rate in viscosity upon temperature decreases first and then increases. When the average coordination number is 2 to 2.6, with the increase of the average coordination number, the average chemical bonding energy and network structure stability of the glass gradually increase, and the change rate in viscosity upon temperature decreases. When is 2.6 to 2.78, with the appearance of As-As/Ge-Ge chemical bonds in the structure, the stability of the glass network is deteriorated, and the glass viscosity changes faster upon temperature. The change rate of glass viscosity is consistent with the structural constraint theory, and the change rate of glass viscosity reaches its minimum value at =2.6.