Optical character enrichment of NdF3 - doped lithium fluoroborate glasses

Optical spectra in combination with Fourier transform infrared FTIR spectra of base undoped lithium fluoroborate glasses and samples that doped with NdF3 were measured before and after subjecting to (8 Mrad) gamma irradiation. Base glass reveals strong absorption in the UV region attributed to unavoidable iron impurity (Fe3 + ions) while gamma irradiated sample shows extended additional peaks related to the photochemical reactions of some Fe2 + impurities transformed to Fe3 + ions by acquiescent positive holes while the induced visible band is related to (BOHC) boron oxygen hole center or (NBOHC) nonbridging oxygen hole center. The NdF3-doped samples display the same strong UV spectra as the undoped sample beside additional characteristic visible absorption peaks due to the presence of Nd3 + ions. UV-Vis. absorption spectra were applied to assess their optical properties, comprising indirect and direct optical energy band gaps taking into account the effect of gamma irradiation. Infrared absorption spectra of the undoped lithium fluoroborate glass reveal characteristic IR bands due to both BO3 and BO4 borate groups as usually observed in various alkali-oxide B2O3 glasses. Suggested BO3F tetrahedral units are advanced to interpret the close similarity of the IR spectra obtained from fluoroborate glass with alkali or alkaline earth oxide borate glasses. The increase of NdF3 content causes minor changes in the IR spectra that can be attributed to the non-conventional loose OH, H2O or similar vibrations while the structural building borate units remain unchanged as evidence from the deconvoluted FTIR data before and after the irradiation process.