Melt Property Variation In Gese2-As2Se3-Pbse Glass Ceramics For Infrared Gradient Refractive Index (Grin) Applications

Melt size-dependent physical property variation is examined in a multicomponent GeSe2-As2Se3-PbSe chalcogenide glass developed for gradient refractive index applications. The impact of melting conditions on small (40g) prototype laboratory-scale melts extended to commercially-relevant melt sizes (1.325kg) have been studied and the role of thermal history variation on physical and optical property evolution in parent glass, the glass' crystallisation behaviour and post heat-treated glass ceramics, is quantified. As-melted glass morphology, optical homogeneity and heat treatment-induced microstructure following a fixed, two-step nucleation and growth protocol exhibit marked variation with melt size. The magnitude of these changes is discussed based on thermal history related melt conditions.