Unveiling Non-isothermal Crystallization of CaO-AlO-BO-NaO-LiO-SiO Glass via X-ray Scattering and Raman Spectroscopy.

The crystallization in glasses is a paradoxical phenomenon and scarcely investigated. This work explores the non-isothermal crystallization of a multicomponent alumino-borosilicate glass via high-energy synchrotron X-ray diffraction, atomic pair distribution function, and Raman spectroscopy. Results depict the crystallization sequence as CaAlO and CaSiO followed by LiAlO with the final compound formation of CaBO. These precipitations occur in a narrow temperature range and overlap, resulting in a single exothermic peak in the differential scanning calorimetry thermogram. The concurrent nucleation of CaAlO and CaSiO is intermediated by their corresponding hydrates, which have dominantly short-range order. Moreover, the crystallization of LiAlO and CaBO is strongly linked with the changes of structural units during the incubation stage in non-isothermal heating. These findings clarify the crystallization of multicomponent glass, which have been inferred from reports but never evidenced via studies.