Tb³⁺as probe ion—Clustering and phase separation in borate and borosilicate glasses

Abstract

Various borate and borosilicate glasses doped with Tb 3+ in a broad concentration range of 1 × 10 18 to 1 × 10 21 Tb 3+ per cm 3 (~0.01 to 10 wt% Tb 2 O 3 ) were prepared and characterized by different methods. Static fluorescence excitation and emission spectra of Tb 3+ in the ultraviolet-visible range were recorded. The fluorescence decay rates of the green emission were measured and fitted. Different lifetimes dependent on different local sites of Tb 3+ ions were detected. To identify these different local sites crystalline terbium borate, TbBO 3 , was prepared and investigated. X-ray diffraction (XRD) and electron microscopy measurements were used. Very strong clustering effects of Tb 3+ ions were detected as preliminary stage of phase separation by formation of a very short decay rate in optically clear borate containing glasses with low optical basicity. In glass samples with phase separation, the Tb 3+ ions were accumulated in the phase with higher optical basicity. The local sites of the Tb 3+ ions in the clusters induce a short lifetime which is similar to the lifetime of crystalline TbBO 3 . Only mono-exponential decay curves for Tb 3+ fluorescence were detected in sodium borosilicate glass with high optical basicity, and in zinc borate glass, without tendency to phase separation. K E Y W O R D S borate, borosilicate, clustering of Tb 3+ , glass forming systems, glass forming systems liquid-liquid, phase transition How to cite this article: Herrmann A, Völksch G, Ehrt D. Tb 3+ as probe ion-Clustering and phase separation in borate and borosilicate glasses. Int J Appl Glass Sci.

Zinc borate glasses: properties, structure and modelling of the composition-dependence of borate speciation

“…S6, ESI †). Two BO 3 peaks with distinctly different lineshapes are present, with an Z = 0.26 for BO S 3 and an Z = 0.45 for BO AS 3 . The peak areas were fixed approximately to those determined by the high field NMR experiments (Fig.…”

“…Zinc borate glasses constitute an interesting binary system because of their attractive properties, like high UV transmission (below 250 nm when made from pure starting materials) and good rare-earth solubility. [1][2][3] Long fluorescent lifetimes of rareearth dopants have been reported for relatively high concentrations of about 10 wt% RE 2 O 3 (RE = Tb, Eu). 2,3 From a chemical point of view, zinc borates present a peculiar case in that their conventional glass forming region begins at very high modifier contents (B54 mol% ZnO).…”

“…[1][2][3] Long fluorescent lifetimes of rareearth dopants have been reported for relatively high concentrations of about 10 wt% RE 2 O 3 (RE = Tb, Eu). 2,3 From a chemical point of view, zinc borates present a peculiar case in that their conventional glass forming region begins at very high modifier contents (B54 mol% ZnO). This is higher than any other binary MO-B 2 O 3 system, where M is a divalent cation (Mg, Ca, Sr, Ba, Cd, and Pb).…”

“…While the NMR data of Harris and Bray showed a clear decrease in tetrahedral boron-oxygen units with increasing zinc oxide content, the Raman spectra reported in a later review on borate glass structure were interpreted as indicating that zinc borate glasses with varying ZnO content have similar structures. 21 Nowadays, advances in instrumentation have allowed more systematic structural investigations of borate glasses with a variety of complementary techniques including infrared (IR), 20,22 Raman, [23][24][25] NMR, 26,27 UV-Visible, 1 photoluminescence, 3 electron paramagnetic resonance, 28 X-ray diffraction (XRD), 29,30 and neutron scattering. 31 Despite these efforts and many others on borate glasses, a consistent description of the composition-dependence of the structure of zinc borate glasses is missing in the literature.…”

Structural, spectroscopic, and radiation shielding properties of Pb2+‐doped borate and phosphate glasses

“…The energy states of Pb 2+ ions are highly affected by the surrounding crystal field and, as a result, allows probing of the glass structure through changes in the optical properties 4,9 . In general, probe ions offer the advantage of detecting the presence of structural units, or even the onset of clustering 10 before bulk spectroscopic methods. For example, for cobalt doped borosilicate glasses, Ehrt et al 11 .…”