Review of the Structures of Phosphate Glasses
About: This article is published in ChemInform.The article was published on 1991-04-30. It has received 58 citations till now. The article focuses on the topics: Phosphate.
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TL;DR: The solubility was seen to decrease with increasing CaO mol%, for all the glasses investigated, and all the compositions showed a gradual decrease in pH with time, and this was accounted for by the release of Na+ and Ca2+ ions into solution.
374 citations
TL;DR: In this article, the formation and ultraviolet (UV) absorption features of the ions were studied in a fluoride phosphate (FP) and two phosphate glasses, and the band separation of the UV absorption spectra was carried out to reveal the components and to determine their spectroscopic properties.
201 citations
TL;DR: In this paper, the Nd3+-doped lithium-zinc-phosphate glasses were prepared by means of conventional melt quenching method and X-ray diffraction results confirmed the glassy nature of the studied glasses.
Abstract: The Nd3+-doped lithium–zinc–phosphate glasses were prepared by means of conventional melt quenching method. X-ray diffraction results confirmed the glassy nature of the studied glasses. The physical parameters such as the density, molar volume, ion concentration, polaron radius, inter-ionic distance, field strength and oxygen packing density were calculated using different formulae. The transmittance and reflectance spectra of glasses were recorded in the wavelength range 190–1200 nm. The values of optical band gap and Urbach energy were determined based on Mott–Davis model. The refractive indices for the studied glasses were evaluated from optical band gap values using different methods. The average electronic polarizability of the oxide ions, optical basicity and an interaction parameter were investigated from the calculated values of the refractive index and the optical band gap for the studied glasses. The variations in the different physical and optical properties of glasses with Nd2O3 content were discussed in terms of different parameters such as non-bridging oxygen and different concentrations of Nd cation in glass system.
74 citations
TL;DR: Degradation studies of the glasses revealed that the rates decreased with increasing B2O3 content and a decrease in degradation rates was also observed as the P2O5 content reduced from 50 to 45 mol%.
Abstract: In this study eight different phosphate-based glass compositions were prepared by melt-quenching: four in the (P2O5)45-(CaO)16--(MgO)24- system and four in the system (P2O5)50-(CaO)16--(MgO)24-, where and 10 mol%. The effect of B2O3 addition on the thermal properties, density, molar volume, dissolution rates, and cytocompatibility were studied for both glass systems. Addition of B2O3 increased the glass transition (), crystallisation (), melting (), Liquidus () and dilatometric softening () temperature and molar volume (). The thermal expansion coefficient (α) and density () were seen to decrease. An assessment of the thermal stability of the glasses was made in terms of their processing window (crystallisation onset, minus glass transition temperature, ), and an increase in the processing window was observed with increasing B2O3 content. Degradation studies of the glasses revealed that the rates decreased with increasing B2O3 content and a decrease in degradation rates was also observed as the P2O5 content reduced from 50 to 45 mol%. MG63 osteoblast-like cells cultured in direct contact with the glass samples for 14 days revealed comparative data to the positive control for the cell metabolic activity, proliferation, ALP activity, and morphology for glasses containing up to 5 mol% of B2O3.
64 citations
Cites background from "Review of the Structures of Phospha..."
...As the ratio MeO/P 2 O 5 increases from 0 to 3, the phosphate structural groups pass from Q(3) to Q [8]....
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TL;DR: Differences in the coordination environments of Ga and Al, network connectivity, and ion aggregation reveal a microscopic model of these glasses which supports the interpretation of the experimental data and provides new insight into the different biological behaviors of Ga- and Al-containing phosphosilicate glasses.
Abstract: The structural properties of phosphosilicate glasses based on the 45S5 Bioglass doped with gallium and aluminum (46.2 SiO2·24.3Na2O·26.9CaO·2.6P2O5·1.0X2O3, X = Ga or Al) are investigated by means of classical molecular dynamics simulations. Structural features of the two compositions are compared with those of the original 45S5 Bioglass in order to relate them to the different known bioactivities of these materials. Differences in the coordination environments of Ga and Al, network connectivity, and ion aggregation reveal a microscopic model of these glasses which supports the interpretation of the experimental data and provides new insight into the different biological behaviors of Ga- and Al-containing phosphosilicate glasses. Although Ga is found predominantly in a 4-fold coordination environment, small amounts of 5- and 6-fold coordinated atoms have been detected depending on the interatomic potential model employed. This suggests its possible intermediate role in phosphosilicate glasses. On the cont...
63 citations
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