Effect of calcium hydroxyapatite on sodium borophosphate glasses: Raman-scattering study

✍ Scribed by J.F Ducel; J.J Videau; M Couzi

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 499 KB
• Volume: 27
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(94)90137-6

✦ Synopsis

A structural study by Raman spectroscopy of the series of glasses with compositions (1 -X)(NaPOa-RNa2B407)-XCas(PO4)30H has been carried out. In connection with previous vibrational results (IR and Raman) for glasses with compositions (1-x)NaPO3-xNa2BnO7, a structural approach can be proposed as a function of X. The introduction of hydroxyapatite in the vitreous NaPO3 (R = 0) produces a shortening of the length of phosphate chains, leading to the formation of (OmPO3) 2-chain ends "cross-linked" by Ca 2÷ cations. In the borophosphate glasses (borate-poor compositions) the breakage effect of hydroxyapatite addition is preferentially located in the POP bridges, also with a "cross-linking" of the borophosphate groups by Ca 2+ cations. Nevertheless, breaks of BOP bridges could also be considered in the range of borate-rich compositions. The "depolymerization" effect of the addition of hydroxyapatite has been correlated with the evolution of the physical and chemical properties.