Extremely high thermometric zero point depression of a Li2O-BaO-SiO2 glass and its causes

Abstract

In a previous publication [1] it was found that the zero point depression of a lithium barium silicate glass was very small, although the difference in field strengths ΔF of the two cations Li+ and Ba2+ is practically zero, thus, a considerable zero point depression should occur [2]. In this paper is proved that the usual quenching temperature of 100 °C is not sufficient to allow dislocations in the structure which are responsible for the zero point depression. Indeed, by raising the quenching temperature above 120 °C a depression appeared the more the higher the quenching temperature. The maximum of depression was reached at a quenching temperature of 180 °C, namely with -2.81 K. This large value is in full agreement with the theoretical prediction. The dependence of the zero point depression on the quenching temperature is also found in common mixed alkali glasses of the sodium potassium type.