STUDY OF LANTHANIDE ZINC PHOSPHATE-GLASSES BY DIFFERENTIAL THERMAL-ANALYSIS

The glass forming regions of the systems Ln2O3-ZnO-P2O5 (Ln = La, Nd, Yb, Er) have been determined subsequent to cooling the melt from 1300-degrees-C. The zone of easily vitrified glass within the La2O3-ZnO-P2O5 system has been investigated in detail by means of differential thermal analysis and from the results it appears that the substitution of ZnO by La2O3 leads to an increase of the glass transition temperature T(g), the crystallisation temperature T(c), and the liquidus temperature T(m). Among the many different parameters which have previously been suggested as a measure of glass forming potential, such as T(g)/T(m), (T(c)-T(g))/T(g), (T(c)-T(g))/T(m), and (T(c)-T(g))/(T(m)-T(c)), the last seems to be a good indicator for the glasses described here.