Spectroscopic features of copper ions in multi-component Na2OPbOBi2O3SiO2 glass ceramics

• Multi-component Na2OPbOBi2O3SiO2: CuO glass ceramics were prepared by melt quenching and heat treatment.
• These glass ceramics are characterized by XRD, SEM, DTA, optical absorption, EPR, FTIR and Raman studies.
• Optical and EPR studies indicated that Cu2+ ions have octahedral coordination with tetragonal distortion.
• Copper ions exist in Cu2+ state they act as modifiers and increase the degree of disorder in the glass ceramic network.

Multi-component Na2OPbOBi2O3SiO2 glasses were crystallised with different CuO contents (0–1 mol % in steps of 0.2) as nucleating agent. These glass ceramics were characterized by XRD, SEM and DTA techniques and indicated the samples contain well defined and randomly distributed grains of different crystalline phases. Spectroscopic studies viz., optical absorption, EPR, FTIR and Raman were also carried out on these glass ceramics. The broad absorption band observed in the wavelength region 550–1000 nm in these glass ceramics and is the characteristic of Cu2+ ions. Optical absorption and EPR studies suggest that Cu2+ ions enter into the lattice as tetragonally distorted octahedral symmetry for which the bonding parameters were evaluated. FTIR and Raman spectra give important information about the nature of various structural units in the glass ceramic matrix. The analysis of these spectroscopic investigations reveals that with increase in the concentration of nucleating agent CuO, copper ions exist in Cu2+ state they act as modifiers and increases the degree of disorder in the glass ceramic network.