Previous spectroscopic studies on vanadium
containing glasses [12–16] have shown that the greenish trivalent
vanadium ions exist in distorted octahedral coordination with oxygen's
and exhibit two characteristic absorption bands at 350–400 nm and
580–680 nm and a third possible band in the UV region originating
from the electron transfer within the vanadium ion itself. The tetravalent
bluish vanadium ions are assumed to exist as vanadyl ions
(VO2+) and exhibit characteristic four spin-forbidden weak bands at
420 nm, 760–860 nm, and at around 1000 nm. The pentavalent colorless ̴
vanadium ions corresponding to the d0 configuration and thus will
not give rise to d–d transitions but give a characteristic UV band at
380 nm. The ratio of each valence of vanadium ions in a glass depends
on the type, the composition of glass and the melting condition [10–14].
Recently, Mirzayi and Hekmatshoar [17] studied ZnO–P2O5 glass
containing higher concentrations of V2O5 varying from 5 to 65 mol%.
They observed that the molar volume data were decreased with increasing
V2O5 content. Moreover, structural studies by Fourier transform
infrared (FTIR) spectroscopy were attributed to the modification
process of the phosphate network. Also, Abdelghany and Hammad
[18] investigate the optical and infrared properties of ZnO–P2O5 glasses
doped with WO3 towards gamma irradiation due to the existence of
heavy transition metal oxide in the glass network like WO3. In this
study the optical and infrared absorption spectra of zinc phosphate
glasses containing vanadium pentoxide were examined to justify the
state of vanadium ions in the zinc phosphate glass. It is due to that