Thermomechanical properties and stability of mixed strontium-zinc borophosphate glasses

Borophosphate glasses of the SrO-ZnO-B2O3-P2O5 system were prepared in 3 co mpositional series of 25ZnO-25SrO-xB(2)O(3)-(50 - x)P2O5, (58.3 - x) ZnO-xS rO-16.6B(2)O(3)-33.33P(2)O(5) and (50 - x)ZnO-20B(2)O(3)-30P(2)O(5) and the changes in their thermomechanical and thermal properties with changes in t heir composition were investigated. The thermal expansion coefficient alpha decreases with increasing B2O3 content, whereas the values of glass transf ormation temperature T-g and dilatation softening temperature T-d increase. The replacement of ZnO by SrO increases both T-g and T-d. From the DSC res ults the value of the the Hruby's criterion K-gl was calculated and changes in the glass-forming tendency with changes in glass composition were discu ssed. (C) 2000 Kluwer Academic Publishers.