Assessment of role of iron ions on the physical and spectroscopic properties of multi-component Na 2 O−PbO−Bi 2 O 3 −SiO 2 glass ceramics.

Multi-component glass ceramics composition Na2O−PbO−Bi2O3−SiO2doped with different concentrations of Fe2O3as nucleating agent were characterised by XRD, SEM (scanning electron microscope) and DTA (differential thermal analysis) techniques. Optical absorption, EPR, FTIR and Raman studies are also carried out on these glass ceramics. Absorption bands observed at about 457, 489, 678 and 820 nm are the characteristics of Fe3+ions whereas the band observed at about 964 nm is due to Fe2+ions. EPR studies suggested that Fe3+ions entered in the lattice as tetragonally distorted octahedral symmetry or rhombic sites at low concentration of Fe2O3, whereas at higher concentration of Fe2O3(beyond 1 mol%), the super exchange type of interactions between multivalency iron ions begin to dominate. FTIR and Raman spectra have revealed the behaviour of various structural units in the glass ceramic matrix. The analysis of these spectroscopic studies indicates that iron ions do exist in Fe3+and Fe2+state. [ABSTRACT FROM AUTHOR]