(a) The studied glasses are based on the basic composition of the undoped sample consisting of Bi2O3 70% SiO2 30%
(mol%) and therefore it is expected the IR vibrational modes are to consist of vibrations due to silicate groups together
with vibrations from Bi–O linkages and some of the vibrational modes are composite broad ones including the two mentioned units whenever they are vibrating within almost the same wave numbers.
(b) The observed IR spectral features show some resemblance to the IR spectra usually obtained from silicate glasses and
crystals [37–39].
(c) The mid-region extending from 400 to 1700 cm_1 is characterized by the appearance of the vibrational modes of building structural network of silicate units.
(d) The near-IR region extending from 2000 to 4000 cm_1 comprises the absorption peaks due to vibrations of water,
hydroxyl (OH) and silanol (SiOH) groups.
(e) The detailed assignments of the IR peaks obtained by the deconvolution of the results of the base undoped glass are
given in Table 1.
(f) Gamma irradiation produces no changes in the number and position of the vibrational modes in the studied glasses due
to the compaction of the network and the presence of high percent of heavy masses bismuth ions.