Confocal Raman spectroscopy of island nuclei formed at the initial stage of quartz glass crystallization

Island nuclei formed on a polished quartz-glass surface upon heating to 1100°C have been investigated by confocal Raman spectroscopy. The structural and chemical composition of islands is shown to be a central nucleus, a shell around the nucleus, and a thin peripheral ring closing this shell. The formation and growth of individual regions of an island nucleus are found to occur in several stages. The shell around the nucleus is mainly formed by α-SiO2 and α-cristobalite nanoparticles with a size ≥40 nm, whereas the α-SiO2 nanoparticles in the nucleus and peripheral ring are 2–15 nm in size.