Multicomponent lead borate-based glasses with various PbO/B2O3 ratio
were synthesized. Series of glass samples (in wt.%): (90 − x)B2O3–xPbO–6Al2O3–
2.95WO3–0.05Cr2O3 and (90 − x)B2O3–xPbO–6Al2O3–3WO3–1Ln2O3 (where
Ln = Eu, Dy; x = 45, 60, 67.5, 72 wt.%) were prepared by mixing and melting appropriate
amounts of metal oxides of high purity (99.99%, Aldrich Chemical Co.) as
starting materials. Reagents were mixed homogeneously together in an agate ball
mill for 2 h. Then, they were melted at 850–1250 ◦C, depending on PbO/B2O3 weight
ratio in chemical composition. Next, they were quenched and annealed below Tg in
order to eliminate internal mechanical stresses.