The structure of lead–indium phosphate and lead–scandium phosphate glasses

Abstract

Lead–indium phosphate and lead–scandium phosphate glasses exhibit a number of useful properties such as the efficient transmission of visible light, a high index of refraction, a low preparation temperature and low melt viscosity, and good chemical durability. The short-range and intermediate-range order structures of a (PbO) 56.3(In 3O 2) 4.2(P 2O 5) 39.5 and a (PbO) 54.2(Sc 3O 2) 3.6(P 2O 5) 42.2 glass were studied by time-of-flight neutron diffraction. From analyses of the measured structure factors of these glasses and those of a pure P 2O 5 glass and a (PbO) 58.8(P 2O 5) 41.2 glass, both the breakdown of the P 2O 5 network structure to short PO 4-chain-like units by the addition of metal oxides and the local environment of the dopant In and Sc ions were characterized. The In–O and Sc–O distance (2.1 Å) is shorter than that of Pb–O (2.52 Å) and the coordination number for Sc–O (6.1) and In–O (5.5) is slightly higher than that of Pb–O (5.3).