New alkali antimonate glasses

Abstract

Glass formation has been investigated in ternary systems Sb 2O 3–PbO–M 2O in which M is alkali Li, Na and K and antimony oxide is the glass former. Alkali elements were introduced as carbonates. The size of the glass forming region is enlarged as alkali ionic radius increases. Binary Sb 2O 3–M 2O glasses were obtained: (100− x) Sb 2O 3– xLi 2O, (10< x<30), (100− x) Sb 2O 3– xNa 2O, (10< x<70), and (100− x) Sb 2O 3– xK 2O, (10< x<90). In ternary systems, PbO content could reach 60 mol%. Temperatures of glass transition, T g, onset of crystallization, T x, and maximum of crystallization, T p, have been measured using differential scanning calorimetry. Depending on composition, glass transition temperature ranges from 240 to 330 °C. The incorporation of alkali oxide increases T g while lead oxide has the reverse effect. Thermal stability range ( T x– T g) was usually between 65 and 266 °C, while no crystallization exotherm was observed in some cases. Density and thermal expansion increases as lead concentration increases. Optical transmission has been measured. The UV cut-off depends on alkali content: samples are yellow and turn green for large K and Na content. These glasses have potential applications as low phonon energy glasses for infrared transmission or active devices.