Temperature Dependence of the Density of Stabilized Magnesium-Aluminoborate Glass at Temperatures below the Glass Transition Temperature

摘要

The density of the glass of the composition 32MgO . 20Al(2)O(3) . 48B(2)O(3) (mol %) (the glass transition temperature is 644 degrees C) in the course of the stabilization process in the temperature range 635-580 degrees C and the temperature dependence of the stabilized glass density d(s) in the range 700-580 degrees C are investigated. The study aims to examine the temperature dependence of the stabilized glass density at temperatures below the glass transition point. The density is measured upon quenching the samples at room temperature via hydrostatic weighing in kerosene with an accuracy of +/- 0.001 g/cm(3). It is established that in the temperature range 650-610 degrees C the density d(s) increases linearly with the temperature decrease. Deviation from the linear dependence d(s)(T) towards lower density values is observed in the temperature range 610-580 degrees C. Therefore, for the stabilized glass of the composition mentioned above in the investigated range below T-g the density first increases linearly with decreasing temperature, after which its growth gradually slows.