The structure of phosphate and borosilicate glasses and their structural evolution at high temperatures as studied with solid state NMR spectroscopy: Phase separation, crystallisation and dynamic species exchange

作者：Wegner Sebastian; van Wuellen Leo^*; Tricot Gregory

来源：Solid State Sciences, 2010, 12(4): 428-439.

DOI：10.1016/j.solidstatesciences.2009.03.021

• Amorphous solids
• Solid state NMR
• In situ NMR
• Crystallisation
• Phase separation
• Structural relaxation

In this contribution we present an in-depth study of the network structure of different phosphate based and borosilicate glasses and its evolution at high temperatures. Employing a range of advanced solid state NMR methodologies, complemented by the results of XPS, the structural motifs on short and intermediate length scales are identified. For the phosphate based glasses, at temperatures above the glass transition temperature T-g, structural relaxation processes and the devitrification of the glasses were monitored in situ employing MAS NMR spectroscopy and X-ray diffraction. Dynamic species exchange involving rapid P-O-P and P-O-Al bond breaking and reforming was observed employing in situ Al-27 and P-31 MAS NMR spectroscopy and could be linked to viscous flow. For the borosilicate glasses, an atomic scale investigation of the phase separation processes was possible in a combined effort of ex situ NMR studies on glass samples with different thermal histories and in situ NMR studies using high temperature MAS NMR spectroscopy including B-11 MAS, Si-29 MAS and in situ Si-29{B-11} REAPDOR NMR spectroscopy.

• 出版日期2010-4