Caloric and Volumetric Properties of the Bi2O3–B2O3–BaO Glass-Forming System for Optical Applications.

The heat capacity and volumetric characteristics of 0.20Bi2O3⋅хBaO⋅(0.80 – х)B2O3 glasses containing 5, 10, 15, and 20 mol % BaO have been measured in the temperature range 300–1000 K. The results, in combination with the glass transition characteristics found, have been used to calculate the standard thermodynamic functions (Т), H°(T) − (0), S°(T) − (0), and G°(T) − (0); density ρ(T); and thermal expansion coefficient α(T) in the range from T → 0 to 900 K for the glasses and supercooled melts. Having a broad transmission window, as demonstrated by our spectroscopic measurements, the glasses have high crystallization resistance according to differential scanning calorimetry results. [ABSTRACT FROM AUTHOR]