Optical parameters, antibacterial characteristics and structure correlation of copper ions in cadmium borate glasses

Abstract

Binary base borate glass of nominal composition (45CdO.55B2O3 mol%) and other samples containing up to 1.6 mol% CuO were successfully prepared using melt annealing route. Fourier transforms infrared (FTIR) spectra of the prepared glasses were studied to identify the structural building groups within the glasses and the role of Cu ions in the matrix arrangement.UV spectra of studied glasses reveal two intense narrow bands originally located at about 235 and 310 nm attributed for the presence of trace iron impurities present on the chemical used for preparation even in the ppm level. Additional analyzed broad visible band centered at about 780 nm appears in the spectra of CuO doped glasses and exhibit splitting at high CuO content. Optical energy gap and other physical parameters including refractive index, density, molar volume, molar refraction, electronic polarizability, and optical basicity reveal strong correlation with copper ion speciation.Both experimental and deconvoluted FTIR spectra of the studied glasses reveal characteristic absorption bands indicating the presence of both triangular and tetrahedral borate groups in their separate vibrational sites. The presence of Cu ions within the doping level is observed to cause no changes in the main characteristic IR bands but limited changes in the intensity of some bands and loosing of the splitting are observed.Antibacterial studies disclose diverse inhibition zone associated with an increase of CuO content and type of bacteria under examination connected with their activity index percent.