title: Novel selenium containing boro-phosphate glasses: preparation and structural study.
abstract: We synthesized a new boro-phosphate glass system with different %mol SeO2 content by conventional melt quenching technique. All samples were obtained in a glassy state with the vitreous structure confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed some non-homogeneous domains on the glasses surface, and their tendency to link each other once the selenium oxide content increases. Energy-dispersive X-ray analysis (EDAX) indicated similar elemental composition in different regions of each sample. X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the elemental composition at the sample surfaces, and Fourier transform infrared (FT-IR) spectroscopy was used to determine the structural groups in the obtained glass structure. Based on FT-IR results, the glass structure at short range order consists mainly of small phosphate units such as pyrophosphate (i.e. P2O7(4-) dimmers or terminating groups at the end of phosphate chains) and some metaphosphate (i.e. PO3(-) middle groups in the phosphate chains) units. The boron atoms are mainly placed in three-coordinated sites in BØ3 or BØ2O(-) units. A small contribution of BØ4(-) units was also detected from the FT-IR spectra of glasses. For SeO2 content higher than 5mol%, the modifier role of selenium ions is strongly reflected on the local structure dominated in this case by pyrophosphate units.
authors.affiliation: Faculty of Physics and Institute of Interdisciplinary Research in Bio-Nano-Sciences, Babes-Bolyai University, Cluj-Napoca 400084, Romania.
authors.forename: R
authors.initials: R
authors.lastname: Ciceo-Lucacel
authors.affiliation: Faculty of Physics and Institute of Interdisciplinary Research in Bio-Nano-Sciences, Babes-Bolyai University, Cluj-Napoca 400084, Romania. Electronic address: teodora.radu@phys.ubbcluj.ro.
authors.forename: T
authors.initials: T
authors.lastname: Radu
authors.affiliation: Faculty of Physics and Institute of Interdisciplinary Research in Bio-Nano-Sciences, Babes-Bolyai University, Cluj-Napoca 400084, Romania.
authors.forename: O
authors.initials: O
authors.lastname: Ponta
authors.affiliation: Faculty of Physics and Institute of Interdisciplinary Research in Bio-Nano-Sciences, Babes-Bolyai University, Cluj-Napoca 400084, Romania.
authors.forename: V
authors.initials: V
authors.lastname: Simon
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D012643:Selenium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D012643:Selenium
keywords: Boro-phosphate glass network; Depolymerization; Glass microstructure; Selenium oxide