New high-density and low-melting glasses in the PbO-PbBr2-PbF2-P2O5 system

A series of new glasses in the PbBr2-PbF2-P2O5 and PbO-PbBr2-PbF2-P2O5 syst ems has been prepared and characterized. The glass-forming regions have bee n explored and the stabilities of the glasses against crystallization studi ed. The composition, densities, characteristic temperatures, and the chemic al stabilities against water of the glasses were measured. Most of the glas ses in these two systems show strong stabilities against crystallization. S ome of the new PbO-PbBr2-PbF2-P2O5 glasses are durable in ambient atmospher e and have densities up to 5.8 g/cm(3). The lowest glass transition tempera ture is as low as 210 degrees C. (C) 1999 Elsevier Science B.V. All rights reserved.