Structural investigations on PbO–Sb2O3–B2O3:CoO glass ceramics by means of spectroscopic and dielectric studies

Abstract

PbO–Sb2O3–B2O3 glasses mixed with different concentrations of CoO (ranging from 0 to 2.0 mol%)were crystallized. The samples were characterized by x-ray diffraction, scanningelectron microscopy and differential scanning calorimetric techniques. The x-raydiffraction and scanning electron microscopic studies have revealed the presence ofCoSb2O6,Co2.33Sb0.67O4,Pb5Sb2O8,Pb3(SbO4)2,PbB4O7 andCo3O4 crystalline phases in these samples. The DSC studies have indicated thespreading of the crystallization from the inside to the surface of the samplesas the concentration of the crystallizing agent is increased. The IR andRaman spectroscopic studies have pointed out the existence of conventionalBO3,BO4,SbO4 andalso CoIII–O structural units in the glass ceramic samples. These studies have further indicated thedecreasing concentration of symmetrical structural vibrational groups with increase in theconcentration of CoO. The results of various studies, namely dielectric propertiesover a range of frequency and temperature, photo-induced birefringence, opticalabsorption, fluorescence and magnetic susceptibility at room temperature of PbO–Sb2O3–B2O3:CoO glass ceramics, have also been reported. The variations observed as a function of theconcentration of crystallizing agent in all these properties have been analyzed in the light ofdifferent oxidation states and environments of cobalt ions in the glass ceramic network.