Sol-gel synthesis and structural characterization of P 2 O 5 -CaO-Na 2 O glasses

Author： Lee In-Ho Foroutan Farzad Lakhkar Nilay J. Gong Myoung-Seon Knowles Jonathan C.

ISSN： 0031-9090

Source： Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B, Vol.54, Iss.3, 2013-06, pp. : 115-120

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Abstract

Ternary phosphate-based glasses in the system P₂O₅-CaO-Na₂O have been successfully synthesized using a new low temperature sol-gel method. The glasses have a fixed P₂O₅ content of 45 or 50 mol% and the CaO:Na₂O ratio was varied. The synthesized systems which remained fully amorphous have been characterized using x-ray diffraction (XRD) and their thermal properties have been examined by differential thermal analysis (DTA). The structure of the phosphate network has been studied as a function of composition using Fourier transform infrared (FTIR) spectroscopy and ³¹P nuclear magnetic resonance (NMR). The XRD results reveal that none of the glasses contain any crystalline phases, while the DTA results reveal increases in the glass transition, crystallization and melting temperatures with decreasing Na₂O content. The FTIR and ³¹P NMR results show that the dried gel has a structure dominated by Q⁰, Q¹ and relatively small amounts of Q² groups, whereas that of the stabilized sol-gel derived glass is composed of mainly Q¹ and Q² species. These results provide several interesting insights into phosphate sol-gel chemistry and indicate their suitability for further study with a view to developing biomedical applications of these glasses in the future.