To achieve glass-ceramics with desired properties, extensive research has been conducted on the correlation between microstructure (e.g., crystallinity and crystallite size) and physical and chemical properties. For example, Peitl et al. studied the effects of crystallization volume fraction and crystallite size on mechanical properties, such as bending strength and fracture toughness, in a biomaterial composed of P 2 O 5 -Na 2 O-CaO-SiO 2 glass. Lu et al.