Short-range order changes induced by heat treatment in yttrium–aluminosilicate glasses
✍ Scribed by V. Simon; R.V.F. Turcu; D. Eniu; S. Simon
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 364 KB
- Volume
- 403
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
Short-range order and local atomic configuration in yttrium-aluminosilicate glasses doped with gadolinium were studied by infrared (IR) spectroscopy, 27 Al magic-angle-spinning nuclear magnetic resonance (MAS-NMR) and Gd 3+ electron spin resonance (EPR) on asprepared and heat-treated samples.
A small amount of yttrium was replaced by gadolinium in the host glass because Y 3+ and Gd 3+ cations are quite similar and gadolinium ions can be used as structural sensor in electron paramagnetic resonance measurements. The results evidence weak changes in the structure of as-prepared glasses with respect to the coordination of aluminium atoms produced by gadolinium doping (0.2 and 0.5 mol%). New IR bands recorded from heat-treated samples are associated with stretching modes of hexacoordinated aluminium in AlO 6 octahedra. The effect of the heat treatment on aluminium environment is estimated by analysing the relative intensity of the component lines of simulated 27 Al MAS-NMR spectra. High-coordinated AlO n species were identified in all samples. EPR results evidence the increase of the number of gadolinium sites with weak crystal field as effect of the structural relaxation.