Gamma irradiation and crystallization effects on the photoluminescence properties of soda lime fluorophosphates host glass activated with Ce4+, Dy3+ or Pr3+ ions

Abstract

Selected rare –earth ions –doped in host Na2O–CaF2 – P2O5 glass were prepared by melting – annealing technique. Multi – characterization of the studied doped (CeO2–Pr2O3 – Dy2O3) glasses and their glass – ceramic derivatives were carried out. Optical, photoluminescence, FTIR spectral analysis were measured before and after gamma irradiation. Optical and PL spectra reveal absorption and emission bands which are characteristic for the specific rare earth doped ions which exhibit distinct shielding behavior in CeO2 – doped glass and limited changes by gamma irradiation with the rest of the rare earth – doped glasses. FTIR spectra show characteristic vibrational bands due to main (PO4) groups with the possibility of (PO3F) units and the rare –earth dopants show minor effects on the IR spectra. Gamma irradiation causes a distinct decrease of the intensities of all the IR vibrational bands due to some suggested changes in the bond angles or bond lengths of the network vibrational units. The diffraction patterns due to the phases of the defined crystalline units in the glass – ceramic crystalline phases formed upon controlled heat treatment indicate the formation two sodium phosphate and sodium fluorophosphates phases beside calcium phosphate phase. The crystallization process is assumed to depend on the phase separation process accomplished by the presence of P2O5 and CaO facilitating the latter crystallization process. The calculated optical parameters are found to depend on the structural arrangements in the glass network and their variations through the introduction of the rare – earth dopant and the formation of non-bridging oxygens.