All these glasses were prepared by using high purity grade of Bi2O3 (Fluka), H3BO3 (Fluka) and Dy2O3 (Fluka)
as raw materials. Each batch weighing about 30 g was mixed homogeneously and melted at 1100qC for 3 h in an
alumina crucible, in air. The melts were poured onto a preheat stainless steel plates. These glasses are in rectangular
designs with a good transparency. All the glasses were annealed below the glass transition temperature to remove
thermal strains. Finally, the as-prepared glass samples were cut and then finely polished to a dimension of 1.0cm x
2.0cm x 0.3cm for properties investigation. By applying Archimedes principle, the weight of the prepared glass
samples was measured in air and in xylene using a 4-digit sensitive microbalance (AND, HR-200). Then, the
density, ȡ, was determined using the relation