Relative proportions of the different crystalline phases formed during annealing of the amorphous precursor. These data are derived from XRD patterns (see text for details). In a) only the mineralogical family are provided, which gives a direct view of the sharp change of the mineralogy produced as a function of T. In b) the different polymorphs of enstatite are presented. The vertical line at 1040 K represents the glass transition temperature determined on quenched glasses.