Spectroscopic Studies and the Effect of Radiation of Alkali Borate Glasses Containing Chromium Ions

The glassy system under investigation is y Li2O - 25 ZnO - 49.9 B2O3 - (25-y) Na2O - 0.1 Cr2O3, where y = = 0, 10, 20, 25 mol%, and it was prepared via traditional melt quenching technique. The optical absorption spectrum of alkali borate glass containing Cr ions reveals a decrease in Cr6+ contributions as the lithium content increases. The strength of crystal field decreases, while the value of both Racah parameters B and C clearly follow a reverse behavior as the content of Li2O increases. The chromium ion has a more ionic environment, and larger numbers of electrons are localized on the D-shell. The obtained ESR signals pointed out the presence of both Cr6+ and Cr3+ states in the host borate glass. FTIR spectra indicated the existence of some bonds, denoting B-O bonds vibrations from BO3 as well as BO4 units. An estimation of the fraction N-4 has been conducted, utilizing the characteristic parameters of IR. Glass samples were influenced by gamma- Irradiation, and a minor change occurred in bond angles and lengths of the structural units of borate. This proves the minor diversity of the IR bands intensity.