%0 Journal Article
%T Optical and FT Infrared Absorption Spectra of 3d Transition Metal Ions Doped in NaF-CaF2-B2O3 Glass and Effects of Gamma Irradiation
%A F. H. A. Elbatal
%A M. A. Marzouk
%A Y. M. Hamdy
%A H. A. ElBatal
%J Journal of Solid State Physics
%D 2014
%R 10.1155/2014/389543
%X Combined optical and FTIR spectroscopy has been employed to investigate the undoped NaF-CaF2-B2O3 glass together with samples containing 0.2% dopant of 3d TM ions before and after gamma irradiation. The optical spectrum of the undoped glass reveals strong UV absorption with two peaks which are related to unavoidable trace iron impurity within the raw materials. Upon gamma irradiation, an induced visible broad band centered at 500ˋnm is resolved and is related to B-O hole center or nonbridging oxygen hole center. TMs-doped samples exhibit characteristic absorption due to each respective TM ion but with faint colors. Gamma irradiation of TMs-doped samples reveals the same induced visible band at 500每510ˋnm in most samples except CuO and Cr2O3-doped glasses. Infrared absorption spectra reveal characteristic vibrational bands due to triangular and tetrahedral borate groups. The introduction of NaF and CaF2 modifies the borate network forming BO3F tetrahedra. The introduction of 3d TMs as dopants did not make any obvious changes in the FTIR spectra due to their low content (0.2%). Gamma irradiation causes only minor variations in the intensities of the characteristic IR borate bands while the bands at about 1640ˋcmˋ1 and 3450ˋcmˋ1 reveal distinct growth in most samples. 1. Introduction Borate glasses belong to a valuable and interesting system which finds applications for optical, thermal, electrical, and biological purposes [1每3]. The basic building oxide for borate glass is B2O3 which consists of triangular BO3 units arranged mostly as boroxol rings (B3O6) [4]. Upon the addition of an alkali oxide, alkaline earth oxide, or heavy metal oxide (e.g., PbO, Bi2O3, and Sb2O3) successive parts of BO3 groups are changed to BO4 groups until certain limit after which the excess additions of the mentioned oxides form nonbridging oxygens. Borate glasses unlike silicate and phosphate glasses possess rich chemistry where different structural groups or super structural units can be formed. The infrared spectra of structural vibrational groups belonging to BO3 or BO4 units have varying wavenumber positions. The BO4 groups are vibrating within the range 800每1200ˋcmˋ1 while the BO3 (B2Oˋ) groups are within the wavenumber 1200每1600ˋcmˋ1 [4]. Some glass scientists have prepared and characterized borate glasses containing alkali, alkaline earth, and divalent halides instead of the respective oxides [5每8]. These types of borate glasses containing halide anions (e.g., Fˋ) possess interesting optical and anionic conduction properties. These authors concluded that these glasses
%U http://www.hindawi.com/journals/jssp/2014/389543/