Configurational entropy as a simple input data for glass science and engineering

The current study seeks to propose new input data for glass science and engineering based on the simple calculations of the configurational entropy. Initially, the configurational entropy of the 15,000 silicate-based glasses with different amounts of alkali or alkaline earth oxide additives (10, 15, and 25 mol%), which were extracted from the SciGlass database, was calculated using S-Conf= -R Sigma(x)(i=1)x(i)lnx(i) formula. In the mentioned formula, S-Conf is the configurational entropy, R is the gas constant, and x(i) is the molar fraction of i element. Then, the relation between entropy and glass properties was theoretically investigated in three conditions. The results indicated that the entropy of the studied glasses is in the range of 0.03R to 2.15R. The results showed positive or negative slopes in the entropy-T g curves for different glass compositions. The found reasons behind the various trends between the entropy and T-g in SiO2-MO2 and SiO2-NO glasses (MO2 and NO are related to alkali and alkaline earth oxides, respectively) could be related to changing the concentrations of non-bridging oxygens, increasing the entropy, and changing the melting points. Also, as can be found from the data, in the SiO2-MO2-NO systems, the reason for different relations of entropy and T-g is related to the slope sign (positive or negative) of SiO2-MO2 and SiO2-NO systems. In conclusion, configurational entropy was proposed as a new input for investigating the glass compound properties. Also, the authors hope that the proposed input data will be considered a new parameter for designing different glass compositions.

Automated summary

The current study proposes new input data for glass science and engineering based on simple calculations of configurational entropy. The configurational entropy of silicate-based glasses with different amounts of alkali or alkaline earth oxide additives was calculated, and the relation between entropy and glass properties was theoretically investigated. The results revealed positive or negative slopes in the entropy-Tg curves for different glass compositions, which could be attributed to changing concentrations of non-bridging oxygens, increasing entropy, and changing melting points.