CHARACTERIZATION OF MANGANESE DOPED SODIUM BORATE GLASSES USING SPECTROSCOPIC METHODS

: Glass samples belonging to the general chemical formula 60B 2 O 3 –(40-x)Na 2 O–xMnO 2 with x=5, 10,15, 20, and 25 mol % are prepared by melt quench method. Characterization of the system was carried out using XRD, SEM and FTIR. The structural changes with composition of the glasses have been studied by FT-IR spectroscopy. FT-IR spectra analysis indicates that MnO 2 is preferentially incorporated into the borate network. Amorphous nature of the system was confirmed by XRD and SEM is used to study the morphology of the glass samples. In the infrared spectral region, the vibration modes of the borate network have four distinct frequency regions (a) The first group of bands, which occur at 1200–1600 cm -1 is due to the asymmetric stretching vibration of the B–O bonds in BO 3 units. (b) The second group lies between 800 and 1200 cm -1 and is due to the B–O stretching of the tetrahedral BO 4 units. (c) The third group is observed around 700 cm -1 and is due to the bending of B–O–B linkages in the borate network. Deformation modes of both types of units are active between 600 and 800 cm -1 [13]. The band at 1390 cm -1 was assigned to B-O stretching vibrations of trigonal (BO 3 ) units in meta borate, pyro borate and ortho borate grups [14]. The intensity of this band is decreasing with the increasing of MnO content. The band at 1210 cm -1 was assigned to B–O stretching vibrations of trigonal (BO 3 ) units in boroxol rings [15]. The intensity of this band increases with the increase of MnO mol%; for higher concentrations, the amplitude of this band decreases. The weak bands evidenced at 1045 cm -1 , 1013 and at 984 cm -1 was assigned to stretching vibrations of B–O bonds of BO 4 units from tri-, tetra- and penta- borate groups The band at 1013 cm -1 gradually disappears with the increase of MnO content by merging into band centred at 1045 cm -1 . The band at 760 cm -1 is assigned to the B-O-B bending vibration of bridges containing one trigonal and one tetrahedral boron and has approximate the same intensity for all the compositional range. In all the IR spectra appears a band at 700 cm -1 relative to the band at 715 cm -1 from the spectrum of vitreous B 2 O 3 , which is due to the bending vibration of B-O-B