Structure and elastic properties of low-temperature sealing phosphate glasses

The structure of 56P(2)O(5)-10B(2)O(3)-4Al(2)O(3)-15Li(2)O-15Na(2)O glasses doped with alkaline earth oxides is investigated by infrared reflectivity measurements and polarized Raman scattering. Vibrational modes are assigned to different types of atomic motion in the glass network. These glasses ex hibit a distribution of chains Of PO4 tetrahedra which are held together by bonding between the non-bridging oxygens of the tetrahedra and the metal c ations. Room temperature ultrasonic velocities (both longitudinal and trans verse) in these glasses are determined by the pulse-echo technique. The exp erimental results are used to obtain elastic constants. The measured values of Young's, shear and bulk moduli for our glasses show a good agreement wi th the theoretically calculated results based on the Makishima and Mackenzi e model. A correlation between glass structure and elastic property is disc ussed in terms of a chain entanglement mechanism Of PO2 groups. (C) 2001 El sevier Science B.V. All rights reserved.