SHORT RANGE STRUCTURE OF SODIUM CALCIUM PHOSPHATE GLASS BY INFRARED AND RAMAN SPECTROSCOPY

Abstract

The aim of this study is to determine the influence of CaO and Na₂O in the short range structure of metaphosphate composition. Sodium calcium phosphate glasses were prepared using melt quenching technique. The crystallinity of the samples was measured using XRD, while the short range structures were measured by IR and Raman spectroscopy. There is no crystalline phase detected from XRD analysis. This result shows that the prepared samples are glasses. Both IR and Raman results show that the main structure unit presents are composed of Q² (middle) and Q³ (branching) tetrahedral units. The Q² units were modified by the presence of Na and Ca ions while the spectrum showed that the P=O become weaken with the increasing of Na content. The spectral shifted to lower frequency at the asymmetric vibration (O-P-O) as Na₂O is replaced by CaO. The asymmetric stretching band of (P-O-P) shifted to higher frequency with the substitution of CaO for Na₂O. It is obviously show that the addition of modifier of CaO and Na₂O changed the structure features of metaphosphate glass composition