ESR as a tool to study short range order phenomena in aluminosilicate glasses
1991; Elsevier BV; Volume: 129; Issue: 1-3 Linguagem: Inglês
10.1016/0022-3093(91)90101-b
ISSN1873-4812
AutoresMarianne Nofz, Reinhard Stößer, Fred Gustav Wihsmann,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoThe following paramagnetic centres could be identified after γ-irradiation of glassy and glassy-crystalline samples in the systems RO–Al2O3–SiO2 (R = Mg, Ca, Sr, Ba, Cd, Pb): Si–O−/h+, Al–O−/h+ or Si–O–Al/h+, Ca+, Cd+ and Pb3+. Pb3+ dominates the ESR spectra of all Pb-containing samples, whereas competitive hole (h+) trapping between Si–O−, Al–O−, Si–O–Al takes place in the other glasses. Ca+ and Cd+ are only detectable in glasses containing a larger amount of the respective oxides. For CaO–Al2O3–SiO2 glasses, the Fe3+ ESR signal at g′ ∼ 4.3 mirrors the ability to stabilize [FeO42]−. This ability corresponds to the Al3+ incorporation into the networks and with the field strengths of the network modifiers. Additionally, the compositional dependence of γ-ray induced redox processes (FeII/FeIII) is described and explained. Study of the ESR fine structure also allows conclusions to be drawn about phase separation and crystallization processes and about pressure induced structural changes in the glasses.
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