Boron speciation and non-bridging oxygens in high-alkali borate glasses

Structure–property correlations in lead borate and borosilicate glasses doped with aluminum oxide

“…The sharpness and symmetry of the [4] B peak are due to a very small quadrupolar coupling constant for the high-symmetry pseudo-tetrahedral site. While multiple distinct [4] B signals are often observed as asymmetric peaks for alkali borate and borosilicate glasses [61,62], the fairly broad linewidths found here (FWHM = 2 ppm) suggest significant disorder and/or a wide range of unresolved tetrahedral sites in all glasses.…”

“…Consequently, the observed signal for [3] B sites often contains overlapping contributions from multiple threecoordinate boron species [32]. However, the isotropic chemical shift of these boron units in crystalline phases [68] increases with depolymerization, a trend recently confirmed in borate glasses [61]. Hence, while the lack of resolution precludes direct quantification, some information is available from the shape and position of the broad and featureless [3] B lineshapes.…”

Addition of platinum and silver nanoparticles to toughen dental porcelain

“…In this case, compressive residual stress would be generated through a possible ion exchange reaction (-Si-O ) by a similar mechanism to that proposed for alkali and alkalineearth elements 25) , which would enhance the mechanical properties.…”

Structural investigation of bismuth borate glasses and crystalline phases

“…The occurrence of wide range of unresolved tetrahedral sites is often observed as an asymmetric [BO 4 ] peak in the NMR spectra of alkali borate and borosilicate glasses [51,52]. Four main types of triangularly coordinated boron species can be found for various loadings of a network modifier in borate glasses: T 3 groups possess three oxygens bridging to other network formers, T 2 groups possess two bridging oxygens and one non-bridging oxygen, T 1 have one bridging and two non-bridging oxygens, and T 0 have three non-bridging oxygens.…”