Some properties of (PbO)x(ZnO)15(P2O5)85-x glasses

Eight glasses were prepared along the line (PbO)(x)(ZnO)(15)(P2O5)(85-x). An increase in the density (3.23 <= rho[g/cm(3)] <= 5.42), in the glass transition temperature (278 = T-g[degrees C] <= 372), in the refractive index (1.56 <= n <= 1.79), and a decrease in the optical gap (5.39 >= E-g[eV] >= 4.65), respectively, was observed with an increase in PbO content. Raman spectra of glasses studied give evidence for phosphate network depolymerisation due to substitution of P2O5 by PbO. The temperature (T) dependence of the optical gap (Eg(T)) in the region 300 < T[K] < 600 was determined and approximated by a simple linear relation (E-g(T) = E-g(T -> 0) - gamma T) with the temperature coefficient (gamma) of the optical gap in the region 4.91 <= gamma x10(4) [eV/K] <= 6.55, respectively.