Crystallization of Precursors to Forsterite and Chromium-Doped Forsterite

The pyrolysis and crystallization of poly(methacrylate) precursors and xerogels of forsterite and chromium‐doped forsterite were studied by in situ high‐temperature, dynamic X‐ray diffraction and thermal analysis. For both types of precursor, crystallization of forsterite occurred at lower temperature when doped with chromium. Also, exotherms above 700°C occurred 50°C lower when chromium was present. When residual carbon in the xerogels was more than ∼1%, an unidentified crystalline intermediate phase formed at ∼800°C. Conversion of the intermediate phase to forsterite was faster than amorphous material. Thus, full crystallinity was attained at a lower temperature when the xerogels had some residual carbon.