Gamma Irradiation Effect on Structural and Spectral Properties of CeO2, Nd2O3, Gd2O3 or Dy2O3 – Doped Strontium Borate Glass

Abstract

Some selected rare – earth (RE) doped strontium borate glasses were prepared by a melting / annealing technique. Optical, FTIR and photoluminescence (PL) spectra were measured before and after gamma irradiation with a dose of 10 Mrad (10 × 104 Gy). The optical absorption spectrum of undoped glass reveals a strong UV absorption band at 231 nm and with gamma irradiation the intensity of the UV peak increases with the generation of an additional induced visible broad band centered at 570 nm. Rare – earth – doped glasses show the appearance of additional small visible peaks in the Nd2O3 and Dy2O3 – doped glasses while the CeO2 and Gd2O3 glasses reveal only the UV absorption peak as for the undoped sample. Gamma irradiation produces an additional induced visible band in the Gd2O3 and Dy2O3 samples only, while CeO2 – doped glass shows obvious shielding resistance to gamma irradiation and its optical spectrum remains unchanged. Infrared absorption spectral measurements indicate that both triangular and tetrahedral borate units (BO3, BO4) are distinctly vibrating at their specific wavenumbers; the BO4 groups within the range 800 – 1200 cm− 1 while the BO3 groups are within the range 1200 – 1450 cm− 1. Gamma irradiation or the addition of rare – earth dopants causes no distinct variations in the number or position of the main IR vibrational bands due to the two coordination states of the borates. Photoluminescence spectra of rare – earth doped glasses show variable responses after excitation depending on the type of RE – dopant. The doped glasses after gamma irradiation (10 Mrad) exhibit darkness or deeping of their colors and show no distinct emission spectra.