Where Bi 32 x O , B 32 x O and Dy O32 x are the mole fractions of the constituent oxides, and Bi 32 Z O , B 32 Z O and
Dy O32 Z are the molecular weights of the constituent oxides.
The optical absorption spectra were recorded at room temperature using a UV-visible-NIR spectrophotometer
(Shimadzu, UV-3100), working in 190-2100 nm.