Relationship between morphology and transparency in glass-ceramic materials

Abstract

This paper is an attempt to understand and interpret optical scattering in composite materials. It focuses on phase-separated glasses and glass-ceramics that maintain transparency at high crystal content. Two approaches aimed at understanding optical scattering are investigated for each example material: (1) a single particle approach and (2) a correlation function approach based on the spatial distribution of the refractive index profile of the material pioneered by Debye. Both methods have shortcomings: the single particle approach cannot take the material’s morphology into account, and it is nontrivial to determine the correlation function. Regardless, the preferred approach is determined for each of the materials investigated. It is shown that optical scattering in glass-ceramics can be controlled to produce a transparent material if the glass-ceramic has a bulk fine-grained structure without an easily recognized “grain size.”