The effect of varying Al 2 O 3 content on the crystallization and microstructure behavior of strontium containing glasses based on the system SrO·4MgO·Al 2 O 3 · 6SiO 2 ·2MgF 2 was investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The glass transition temperature (T g ) and first crystallization peak temperature (T p 1 ) reduced with decrease in the alumina content. Glasses with x≥1.5 exhibited a second crystallization peak temperature (T p 2 ). The first crystallization peak temperature (T p 1 ) corresponded to the formation of strontium fluorophlogopite and second crystallization peak temperature (T p 2 ) corresponded to the formation of strontium aluminum silicate. © 2013 Elsevier Ltd and Techna Group S.r.l.