Tetrahedral BO4 Units Research Articles

Effect of mutual modification by BaO and BaF2 on the structure and properties of BaO–BaF2–B2O3 glasses

Oxy-fluoroborate glasses of the composition xBaF2·(45-x)BaO·55B2O3 (0 ≤ x ≤ 45 mol%) have been prepared by the normal melt-quenching technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm that the glassy matrix contains amorphous and/or crystalline phases depending on BaF2 concentration. Scanning electron microscopy (SEM) shows agglomerates consisting of clusters in micro-scale separated from the amorphous phase. Fourier-transform infrared (FTIR) spectra reveal that BaF2 partially modifies the borate matrix as in the binary BaF2–B2O3 glasses. Values of fraction N4 of four coordinated boron atoms calculated from FTIR spectra agree with nuclear magneitic resonance (NMR) data. N4 increases at the expense of non-bridging planar trigonal (BO3) units at low concentrations of BaF2 while at higher concentrations, N4 increases at the expense of tetrahedral BO4 units. Density seems to be constant while molar volume increases from 27.51 to 30.31 cm−1 with increasing BaF2 content. It is found that the volume of structural units by BaF2 is greater than those related to BaO. Tg have a linear decrease from 580 to 485 °C with increasing BaF2 concentration. A structural view is presented for the role of BaF2, obtained based on N4 data obtained from NMR and FTIR analysis.

Effect of Bismuth on Physical and Spectroscopic Properties of ZnO-Li2B4O7-TbF3 Glasses

The effect of Bismuth on zinc-lithium tetra borate glasses were discussed based on structural, physical, and spectroscopic properties. Glass systems of Bi2O3-ZnO-Li2B4O7-TbF3 [BZLT] were cast by melt-quench process. Transparent glasses were analysed by diffracted Roentgen X-rays. Peak free and broad nature X-ray diffraction revealed the amorphous arrangement prevailing in these glasses. Density was estimated using the Archimedes principle. Bismuth grossly affected the density of BZLT glasses by increasing its value 2.722 gm/cc [BZLT-0] to 4.6739 gm/cc [BZLT-40]. Optical absorption provides valuable information about optical band gap energy and Urbach energy and some of its derived physical quantities. The effect of bismuth is felt in decreased Eopt values [3.312 eV in BZLT-0] [2.619 eV in BZLT-40] in BZLT glasses. Bismuth altered the structure of the borate network by forming non-bridging oxygens which in turn reduced the band gap energy by large margin (ΔEopt = 0.693 eV). Fourier transform infrared spectroscpy and Raman studies revealed the presence of several triangular BO3 and tetrahedral BO4 and BiO3 units and also the existence of metal cation vibrations and supported the large deviations in the optical bandgap energies. Election paramagnetic resonance studies support the presence of Tb3+ ions and absence of Tb4+ions in BZLT glasses.

An investigation of the structural and optical properties of modified barium magnesium fluoroborate glasses with hafnium oxide (HfO2)

Glasses of nominal composition xHfO2–(35-x)B2O3–15MgF2–35BaO, where x ranged from 0 to 0.2 mol% were fabricated using a melt-quenching technique. Structural characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and Raman spectroscopy, were employed to elucidate the glass network structure. The XRD patterns confirmed the amorphous nature of the studied glasses, while the FTIR and Raman spectra revealed that the incorporation of HfO2 may led to a transformation of trigonal BO3 units to tetrahedral BO4 units in the borate glass network. Deconvolution analysis of the FTIR and Raman bands provided quantitative insights into the extent of this structural rearrangement as a function of HfO2 content. UV–Vis absorption studies demonstrated that the optical bandgap of the glasses was widened with increasing HfO2 additions. This blue shift in the absorption edge was attributed to the increased formation of bridging oxygen bonds and reduced non-bridging oxygen content in the glass network. The results indicate that the studied glasses exhibit excellent compositional tunability through the incorporation of HfO2. The structural modifications and concomitant optical property enhancements suggest the potential of this glass system for various integrated photonic applications where low phonon energy and tailored transparency are highly desirable. The present work introduces a comprehensive investigation of the structural and optical property modifications in barium magnesium fluoroborate glasses induced by the addition of hafnium oxide (HfO2).

Synthesis, optical, and spectroscopic studies of bismuth boro-tellurite glass system containing BaO and V2O5

A melt quenching technique was used for the preparation of xBaO–(30-x)TeO2–35Bi2O3–33B2O3–2V2O5 (5 ≤ x ≤ 25 mol%) glasses. The structural modifications are studied by X-ray diffraction, DSC, optical, infrared spectroscopy, and Raman as a function of BaO mol%. The progressive incorporation of BaO mol% in the BTBiBV glasses decreases the optical band gap values as the number of free electrons increases with the creation of additional NBOs. The FTIR spectra of the prepared glasses consist of BO3 trigonal and BO4 tetrahedral units while TeO2 changes to TeO3 andTeO4 structural units. The Raman spectra shows that the replacement of BaO with TeO2 decreases the concentration of Te–O–Te linkages within the volume of host glass, which increases the concentration of Ba–O–Te linkages along with BO3 units. Due to this, the overall glass formers connectivity decreases which intern to the creation of NBOs. Moreover, the research highlighted that BTBiBV-5 glasses have exceptional optical properties making them promising materials for photonics, optoelectronics, and optical communication device applications.

Development of Dy3+ doped lithium magnesium borate glass system for thermoluminescence based neutron dosimetry applications

Abstract The manuscript reports the synthesis of Dy3+ incorporated lithium magnesium borate glass by melt quenching technique. FTIR study revealed the presence of both BO3 as well as tetrahedral BO4 units through their characteristic frequencies. Photoluminescence (PL) study of unirradiated samples confirmed the presence of Dy dopant in the ‘+3’ oxidation states from the characteristic emissions at 482, 578, 666 and 716 nm corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2, 4F9/2 → 6H9/2 transitions, respectively. Thermal neutron and gamma irradiated PL emission and lifetime characteristics were discussed in details based on the different defect centers. Thermal neutron irradiated TL study showed that the material has a broad and single dosimetry glow peak at about 450 K which showed high fading due to low temperature peak. TL based neutron sensitivity of LMB: Dy3+ was found to be about 37.4 times less than that of standard TLD-100 (LiF: Mg, Ti) powder. The net TL response from about 3 to 83 mSv of neutron dose was found to be linear (Adj. R2 = 0.9994) which is one of the most desirable properties for dosimetry applications. In addition, the TL trap parameters were evaluated using both deconvolution of TL glow curve and peak shape method as suggested by Chen which were found to be matching with each other.

Chemical durability and shielding study of borosilicate glass systems from solid municipal waste ash for radiation shielding applications

Based on municipal solid waste (MSW) ash as a main raw material, three novel borosilicate glasses with the composition of 70 waste + 20 borax + 10 Na2O + x ZrO2, where x = 0, 0.1 or 0.3 (wt. %),were prepared by the traditional melting-annealing technique. The prepared glasses were analyzed by EDX analysis, revealing the rich compositions of the prepared glasses correlated to the MSW ash used by 70 wt.% in preparing glasses. Some optical, chemical and radiation shielding properties of the prepared glasses were investigated. Either Zr addition or 80 kGy of gamma radiation revealed improvement of the glasses optical transmittance and chemical durability in neutral dis H2O, alkaline 0.1 N NaOH and acidic 0.1 N HCl leaching media for 70 days. Electron spin resonance (ESR) revealed the same spectra before and after irradiation, referring to the prevention of free radical formation by irradiation.The shielding parameters were measured by the experimental gamma spectroscopy (NaI detector) and the theoretical Phy-X/PSD software e.g., linear attenuation coefficients (LAC) and the findings revealed high unanimity among them at photon energies 0.662, 1.173 and 1.333 MeV. Another shielding parameters were also studied e.g., mass attenuation coefficients (MAC), effective atomic number (Zeff), effective electron density (Neff) and effective conductivity (Ceff). Presence of various metal oxides and the host trigonal BO3 and tetrahedral BO4 and SiO4 units, and ZrO2 provide the glasses compactness and effectual stability against ionizing irradiation. The prepared borosilicate glasses have highly strong and compacted structures that can inhibit the passage of radiation photons, because of the variety of many glass network formers, intermediates and modifiers present in the used waste ash. The results indicate the highly economic benefit of the prepared glasses, where the useless MSW ash are used mainly by 70 wt.% to produce effective borosilicate glass systems for promising radiation shielding purposes, especially 0.3 Zr borosilicate glass that has the best radiation shielding properties.

Fabrication of zirconium borosilicate glasses using municipal waste ash for radiation shielding applications; optical and structural investigations

In this study, three borosilicate glass systems were successfully prepared by using the melting–annealing technique from municipal waste ash and doped with ZrO2 at 0, 0.1, and 0.3 wt.%. The glasses were analyzed by electron dispersive X-ray spectroscopy (EDX), which indicated their rich compositions with various metal ions, and X-ray diffraction analysis (XRD) confirmed their amorphous glassy nature. The effects of gamma radiation at 80 kGy on the optical, physical, structural, and chemical properties of the glasses were evaluated. The optical spectra contained ultraviolet peaks at 260–340 nm and visible peaks at 440–470 nm due to the different valence states of transition metal ions, e.g., Ti4+/Ti3+, Cu2+/Cu+, Zn2+, Fe3+/Fe2+, and/or Zr4+. The optical band gap energy (Egap) decreased from 2.0 to 1.0 eV and from 2.8 to 1.90 eV for indirect and direct transitions after irradiation, respectively, whereas the linear refractive index (n) increased. Fourier transform-infrared spectroscopy (FTIR) indicated high structural stability against irradiation due to the connected borosilicate network comprising trigonal BO3 and tetrahedral BO4 and SiO4 units. The band at 960 cm−1 in the undoped and 0.1% Zr4+ glasses shifted to 980 cm−1 in 0.3% Zr4+ glass because of the different compositions and silica contents of the glasses. Analysis of the chemical durability of the glasses in H2O at 100 °C indicated their high chemical stability before and after irradiation with a weight loss not exceeding 0.05%. BO3, BO4, SiO4, transition metal ions, and ZrO2 all contributed to the compact structure of the glasses, and their high stability against irradiation indicates the potential applications of the glasses in radiation shielding.

The effect of cobalt/copper ions on the structural, thermal, optical, and emission properties of erbium zinc lead borate glasses

A host glass network of 70B2O3–10Pb3O4–18ZnO–2Er2O3 (ErCoCu1) was proposed and the impact of 1 mol% of Co or/and Cu ions on its structural, thermal, optical, and green emission properties was studied extensively. The X-ray diffraction spectra confirmed the amorphous structure of the produced glasses. Density and density-based parameters behavior showed that the Co or/and Cu ions fill the interstitial positions of the proposed ErCoCu1 network, causing its compactness. Both ATR-FTIR and Raman Spectra affirmed the formation of the fundamental structural units of the borate network, B–O–B linkage, BO3, and BO4. Additionally, the penetration of Co or/and Cu ions inside the ErCoCu1 converts the tetrahedral BO4 units to triangle BO3 causing its richness by non-bridging oxygens. The addition of Co or/and Cu reduces the glass transition temperature as a result of the conversion of the BO4 to BO3 units. Optical absorption spectra for the host glass ErCoCu1 showed many of the distinguished absorption bands of the Er3+ ion. Penetration of Co ion generates two broadbands referring to the presence of Co2+ ions in both tetrahedral and octahedral coordination and Co3+ ions in the tetrahedral coordination. In the Cu-doped glasses, the characteristic absorption bands of Cu2+ and Cu+ were observed. A green emission was generated from the ErCoCu1 glass under 380 nm excitation wavelength. Moreover, no significant effect of Co or/and Cu on the emission spectra was recorded. The considered glasses had appropriate properties qualifying them for optoelectronics and nonlinear optics applications.

Structural, thermal, and DC conductivity properties of WO3–P2O5 glasses doped with B2O3

AbstractIn this study, glasses in composition 70WO3–(30 − х)P2O5–хB2O3 (0 ≤ х ≤ 20 mol%) were prepared by melt quenching method. The glass formation, structure, and thermal and electrical properties are discussed. Homogeneous glasses were obtained at x = 0–10 mol% B2O3, whereas glasses with x = 15 and 20 contain microinclusions of WO3. The glass transition temperature decreases from 709 to 531.6°C with increasing B2O3 content, as well as the crystallization temperature and the thermal stability. The structure of the glasses was studied by Raman spectroscopy and infrared spectroscopy. The Raman spectra are characterized by a band near 995 cm−1, a broad band at 788–800 cm−1, and a band near 675 cm−1 ascribed to vibrations of W–O–P, W–O–W, and P–O–B bonds, respectively. The Fourier‐transform infrared spectra show vibrational bands due to characteristic phosphate and borate groups. Tetrahedral BO4 units prevail in the structural network. The electrical conductivity of the glasses decreased with x content due to the growth of WO3‐deficient regions.

Effect of CeO2/Er2O3 co-doping on spectroscopic properties of zinc fluoroborate glasses

The glass system 75B2O3—4.5ZnF2—0.5 Er2O3–(20-x) ZnO- x CeO2, x = (0 ≤ x ≤ 1 mol. %) in this article was produced using the melt-quenching technique. Utilizing FT-IR techniques, the structural specifics of manufactured glasses are studied. The and fractions will be used to explore the transformation in the glass system that has been obtained. The BO3 and BO4 units coexisted in the glass composition, based on FT-IR spectra. Cerium ions appear to change trigonal BO3 units into tetrahedral BO4 units, according to preliminary FT-IR studies. The Judd-Ofelt theory is used to calculate the optical properties of the current glass that is co-doped with Er/Ce. Energy levels and line strengths of the Er3+ ion are evaluated. The current work additionally provides optical gains, emission/absorption cross-sections, and optical intensity data. The compound containing 0.6 mol% provided the greatest values for optical parameters like intensity parameters and optical gain compared to all other concentrations employed in this study.

The impact of electron beam irradiation on some novel borate glasses doped V2O5; Optical, physical and spectral investigation

New borate glass systems with composition of 56B2O3 + 25Li2O + 10Na2O + 5CaO + 2SrO + 2Al2O3 + 0.5 TeO2 + x V2O5, where × = 0.2 or 0.3 (wt. %), were fabricated via the traditional melting-annealing method at low temperature (650–750 °C). Some of the glasses optical, physical, chemical and spectral measurements were investigated within the impact of electron beam (EB) irradiation up to 8 kGy. UV–visible spectra revealed peaks at ∼ 290 and ∼ 300 nm for 0.2 and 0.3 V2O5 glasses, respectively. In addition to broad visible band at ∼ 580 nm owing to the participation of vanadium ions as V5+ with possible conversion to V3+/V4+ under the effect of EB irradiation. FTIR spectra revealed the main trigonal BO3 and tetrahedral BO4 units with an increase in N4 values by the progressive EB irradiation. ESR spectra revealed a gradual increase in intensity with irradiation doses. While, testing chemical durability in distilled H2O at 100 °C reveals a good manner before and after irradiation process. Some physical parameters e.g. optical energy gap (Eoptdirect and Eoptindirect), Urbach energy (EUrbach), refractive index (n) and spectral distribution (k) showed also a gradual decrease with continual irradiation owing to the gradual generating of non-bridging oxygens NBOs and progressive transformation of BO3 to BO4 units. The overall data displayed some dosimetric properties of the two studied glasses with a useful dose range 3–8 kGy of EB radiation. The study recommends usage of glasses as glass dosimeters in medical sterilization, industry and food irradiation processing.

Crystal structure of MgK0.5[B6O10](OH)0.5·0.5H2O, poly[dimagnesium potassium bis(hexa-borate) hy-droxide monohydrate

The solvothermal reaction of H3BO3, KCF3SO3, Mg(CF3SO3)2 and pyridine led to a new alkali- and alkaline-earth-metal borate, MgK0.5[B6O10](OH)0.5·0.5H2O. Its structure features an intricate three-dimensional framework built from [B6O13]8- clusters, thus resulting in a six-connected achiral net with high symmetry. Each [B6O13]8- building block is composed of three trigonal BO3 and three tetra-hedral BO4 units, with these BO4 units being further connected to neighboring BO3 units, giving rise to an oxoboron cluster of the general formula [B6O10]2-.

Structural, physical and ultrasonic studies on bismuth borate glasses modified with Fe2O3 as promising radiation shielding materials

Fe-bismuth borate glass systems of composition; (70-x) B2O3+ 5 Bi2O3+15 MgO+ 5 Na2O+5 Al2O3+x where x = 0, 0.5, 1, 1.5 mol% Fe2O3 were prepared thru the known melting annealing procedure. Some of their structural, optical, physical and ultrasonic properties were measured and interpreted towards gamma irradiation up to 60 kGy. FTIR spectra display vibrations of the main triangular BO3 and tetrahedral BO4 units, BiO6 polyhedral and AlO4 units. The deconvoluted spectra diplay limited changes in the glasses structural units. UV–visible absorption spectra show peaks at∼ 220, 248 and 270 for Fe-free glass with a cutoff shift to ~ 320 and 360 nm for Fe-containing glasses. The UV peaks are correlating to absorption of the triplet Fe3+ ions and trivalent Bi3+ions. Either the optical or vibrational bands obtain an apparent moral stability against gamma irradiation doses especially before 60 kGy. Density, molar volume, optical energy band gap (Eopt), other physical parameters and ultrasonic properties e.g. longitudinal and shear ultrasonic velocities, elastic moduli, microhardness and ultrasonic attenuation coefficient (α) reveal also high stable performance against irradiation process. Presence of the polarizable Bi3+ ions helps in blocking radiation photons passage and Fe2+/Fe3+ enhances the absorption of defect color centers caused by irradiation. Additionally, the condensed AlO4 units provide the glasses structures and compactness. The stable behavior and superior optical visibility of the prepared Fe-bismuth borate glasses properties against ionizing radiation, recommend their promising usage as suitable radiation shielding candidates for protecting specialists and patients in healthcare, dentistry, veterinary and industrial environments.

Lanthanide (Ce, Nd, Eu) environments and leaching behavior in borosilicate glasses

Borosilicate glasses will be used to stabilize the high-level radioactive wastes for disposal in a geological repository. Understanding the effects of actinide addition to a borosilicate glass matrix is of great importance in view of waste immobilization. Lanthanides were considered as chemical surrogates for actinides. The local structures of Ce3+, Nd3+ and Eu3+ ions in borosilicate glass, have been investigated by synchrotron radiation based techniques. The atomic parameters, such as bond lengths and coordination environments derived from X-ray diffraction, in combined with Reverse Monte Carlo simulations show correlation with X-ray absorption fine structure data. The lanthanide ions are in the common network with the tetrahedral SiO4 and with the mixed trigonal BO3 and tetrahedral BO4 units. Second neighbor atomic pair correlations reveal that the Ce3+, Nd3+ and Eu3+ ions are accommodated in both Si and B sites, supporting that the lanthanide-ions are stabilized in the glass-matrix network. Microscopy and microanalysis provided information on the amorphous state and on the major elemental composition of the high lanthanide-concentration samples. The release of matrix components (Si, B, Na, Ba, Zr) is higher than that of lanthanides (Ce, Nd, Eu). Both types of elements show a decreasing release tendency with time.

Optimizing of optical and structure characters of borate glasses by different concentration of CoO: Electron beam irradiation dosimetry

Un-doped and cobalt oxide (CoO) doped lithium borate glasses with different concentrations (0.1, 0.3, and 0.5 mol %) were prepared by the conventional melting process at an approximate temperature of 1100 °C. The X-ray diffraction analysis showed the amorphous structure of the prepared glasses. Fourier transform infrared (FTIR) spectra of the synthesized glasses proved a gradual change in the glass network due to the transformation of the trigonal BO3 units into the tetrahedral BO4 units with the formation of non-bridging oxygens with the increase of CoO concentration and irradiation dose to 60 kGy. Minor changes occurred in the vibration bands of the FTIR spectra of lithium borate glasses with the increase of CoO concentration, where a slight lowering and broadening in the already existed peaks for BO3 and BO4 can be observed indicating the well dissolved of CoO in the glass matrix. The optical absorption spectra of the glasses before and after electron beam irradiation with different doses have been studied and the optical band gap, Urbach energy and refractive index also have been obtained. The results showed broad and strong absorption peaks in the visible range; these peaks can be attributed to the presence of the cobalt ions in the octahedral and tetrahedral configurations with different valence states. It is observed that the prepared glasses have a high sensitivity to electron beam irradiation which makes these glasses applicable to be used as dosimeters especially with low doses.

Expanding the chemistry of borates with functional [BO2]\u2212 anions

More than 3900 crystalline borates, including borate minerals and synthetic inorganic borates, in addition to a wealth of industrially-important boron-containing glasses, have been discovered and characterized. Of these compounds, 99.9 % contain only the traditional triangular BO3 and tetrahedral BO4 units, which polymerize into superstructural motifs. Herein, a mixed metal K5Ba2(B10O17)2(BO2) with linear BO2 structural units was obtained, pushing the boundaries of structural diversity and providing a direct strategy toward the maximum thresholds of birefringence for optical materials design. 11B solid-state nuclear magnetic resonance (NMR) is a ubiquitous tool in the study of glasses and optical materials; here, density functional theory-based NMR crystallography guided the direct characterization of BO2 structural units. The full anisotropic shift and quadrupolar tensors of linear BO2 were extracted from K5Ba2(B10O17)2(BO2) containing BO2, BO3, and BO4 and serve as guides to the identification of this powerful moiety in future and, potentially, previously-characterized borate minerals, ceramics, and glasses.

Gaining insights on high-temperature thermal conductivity and structure of oxide melts through experimental and molecular dynamics simulation study

The high-temperature thermal conductivity of CaO–Al2O3–B2O3 melts was measured using the hot-wire method between 1550 and 1850 K. From the structural analysis of the as-quenched melts based on Raman spectra, X-ray photoelectron spectroscopy (XPS), magic-angle spinning nuclear magnetic resonance (MAS-NMR) and molecular dynamics simulation, the relationship between thermal conductivity and melt structure was discussed. When the Al2O3/B2O3 ratio was fixed at unity, the CaO increments from 40 to 60 mol pct lowered the thermal conductivity. The three-dimensional network structures were depolymerized, resulting in more orthoborates and fewer bridging oxygens. Al[4] population increased with the CaO addition, while the fraction of B[4] species decreased relative to B[3] species. When the CaO content was fixed at 50 mol pct, the thermal conductivity initially decreased with B2O3 increments up to 25 mol pct. The proportion of Al–O–Al linkages dropped, while the borate units mostly remained in two-dimensional forms. Greater addition of B2O3 over 25 mol pct enhanced the thermal conductivity mainly due to the conversion of BO3 triangular units to BO4 tetrahedral units. The structural changes are consistent with the topological network connectivity evaluated from the ring statistics.

Thermal and structural characterization of lithium borate glasses doped with Fe(III) ions: The role of alkaline earths

Abstract The quaternary glass system Li2O-RO-B2O3–Fe2O3 (here R = Ca, Sr and Ba) has been prepared by traditional quenching method. The observed XRD pattern validate the amorphous nature of the synthesized quaternary glass system. DSC studies are employed to analyze the thermal characteristics of prepared quaternary glass system. FT-IR and Raman studies are the two intensive spectroscopic techniques and which are employed to examine the structural details of Li2O-RO-B2O3–Fe2O3 (where R = Ca, Sr and Ba) quaternary glass system. These spectra have showed that the prepared glass samples consists of triangular BO3 units and tetrahedral BO4 units. To analyze the structural changes in the prepared quaternary glass system the fraction of BO4 atoms (N4) and BO3 atoms (N3) were projected. Optical absorption studies are employed to determine the optical band gap ( E opt asf ) values of prepared quaternary glass system. To classify the simple oxide materials, the Electronic polarizability ( α o 2 − ), optical basicity(Λ) and interaction parameter ( A * ) were also scrutinized.

Structural investigation of borosilicate glasses containing lanthanide ions

High level radioactive actinides are produced as a side product in reprocessing spent nuclear fuel, for which safe long-term-inert immobilizer matrices are needed. Borosilicate glasses are of great potential amongst the candidates of suitable inert materials for radioactive waste immobilization. Understanding the effects of actinide addition to a borosilicate glass matrix is of great importance in view of waste immobilization. Here we present structural studies of a simplified glass-matrix, − 55SiO2·10B2O3·25Na2O·5BaO·5ZrO2 - upon adding lanthanide (Ln-)oxides: CeO2, Nd2O3, Eu2O3, in two different concentrations 10% and 30w% each, to investigate the effects of lanthanides (Ln) taken as chemical surrogates for actinides. Neutron diffraction combined with of Reverse Monte Carlo simulations show that all investigated glass structures comprise tetrahedral SiO4, trigonal BO3 and tetrahedral BO4 units, forming mixed [4]Si-O-[3]B and [4]Si-O-[4]B linkages. 11B Magic Angle Spinning Nuclear Magnetic Resonance is indicative of simultaneous presence of trigonal BO3 and tetrahedral BO4 units, with spectral fractions strongly dependent on the Ln addition. Ln-addition promote the BO3 + O-→[BO4]– isomerization resulting in lower fraction of boron in BO3, as compared to BO4 units. Raman spectra, in full agreement with neutron diffraction, confirm that the basic network structure consists of BO3/trigonal and SiO4/BO4 tetrahedral units. Second neighbour atomic pair correlations reveal Ce, Nd, Eu to be accommodated in both Si and B sites, supporting that the borosilicate-matrix well incorporates Ln-ions and is likely to similarly incorporate actinides, opening a way to radioactive nuclear waste immobilization of this group of elements in a borosilicate glass matrix.

“Gamma Rays Interactions on Optical, FTIR and ESR Spectra of Alkaline Earth Binary Borate Glasses”

Abstract Alkaline earth binary borate glasses with the composition of (100-x) B2O3 + X (BaO, CaO, SrO) where x=22, 32 or 42 wt. % were prepared by melting annealing technique. Some of their physical and spectroscopic properties have been studied before and after gamma irradiation such as Density, oxygen packing density, molar and specific volumes, as well as optical UV-visible absorption, optical energy gap (Eopt), FTIR and ESR spectroscopy. The UV-visible spectra show a shifting of the optical edge to higher wavelengths with increasing the polarizability of the introduced modifier ion and the dose of gamma radiation. FTIR spectra show the vibrational bands of the structural borate groups; the triangular BO3 and tetrahedral BO4 units at 1200-1600 cm-1 and 800-1200 cm-1 respectively. ESR spectra show a constant behavior of the glasses at the low doses of radiation up to 60 kGy but show high effect of radiation at the higher doses due to the formation of more paramagnetic defects and free radicals.