Study the effect of alkali/alkaline earth addition on the environment of borochromate glasses by means of spectroscopic analysis

• Published in: Journal of alloys and compounds Vol. 586; pp. 605 - 610
• Main Author: Ahmad, F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-02-2014; Elsevier
• Subjects: Borochromate glasses; Chromium; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystals; Density; Electron paramagnetic resonance and relaxation; EPR spectra; Exact sciences and technology; Field strength; FT-IR spectroscopy; Glass; Ligand field theory; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Mathematical analysis; Optical basicity; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Short range order; Spectra; UV–VIS optical absorption; Borochromate glasses; UV–VIS optical absorption; FT-IR spectroscopy; EPR spectra; Optical basicity; Ligand field theory; Molar volume; FT-1R spectroscopy; Racah coefficients; Refractive index; Liquid state quenching; XRD; Covalent bonds; Borate glasses; Quaternary systems; Chromium oxide; Ligand field; Ultraviolet visible spectrum; Lithium oxide; Urbach rule; Electron paramagnetic resonance; Absorption spectra; Fourier-transformed infrared spectrometry; Strontium oxide; UV-VIS optical absorption
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.10.105

•The xSrO–(30−x)Li2O–65.5B2O3–0.5Cr2O3 (x=0,5,10,15 and 20mol%) glassy system was prepared by a quenching method.•XRD patterns reveal the amorphous nature of the present glass matrix.•Spectroscopy analysis shows an increase in Cr3+ concentration which acts as modifiers.•UV-optical measurements show a decrement of optical band gap energy and an increment of refractive index.•The electronegativity plays an important role in deforming the crystal field around the transition metal ions.
Glassy samples of composition xSrO–(30−x)Li2O–65.5B2O3–0.5Cr2O3 (x=0, 5, 10, 15 and 20mol%) were fabricated by using the melt quenching technique method. The investigated glass samples have been examined using powder X-ray diffraction (XRD) technique. FT-IR spectroscopy, density, optical absorption in UV–VIS range and the calculated optical basicity and EPR spectra were recorded. The obtained results of the XRD spectra of all the samples confirmed the amorphous nature of the prepared glasses. The spectrum of FT-IR reveals that, the BO4 units decrease with increasing SrO content and the non bridging oxygen’s increase. The obtained density and the molar volume exhibit linear increase with increasing SrO content. Optical measurements show a decrement of optical band gap energy and steepness parameter as well as an increment of the Urbach energy and refractive index. The ligand field parameters calculation shows that, the values of the crystal field strength and the degree of covalency between ions increase as well as the interelectronic d–d repulsion Racah parameters decrease. The increase of the (Dq/B) ratio with increasing SrO content which reaches to 2.58 for x=20mol%, suggesting that strong crystal field strength. An increase of the electronegativity by replacing Li2O by SrO, causes a decrease of the glass matrix basicity. The obtained EPR parameters indicate that the increasing of Cr3+ signal intensity and spin density. The analysis of the results indicated that, the chromium ions are present in trivalent covalent in the octahedral coordination are more predominate.