One of the most common therapeutic surface reactive bioresorbable implant material used nowadays is bioactive glass 45S5. However, being amorphous in nature, its usage in load bearing applications is ineffective due to its poor mechanical properties. A novel idea of toughening bioactive glass 45S5 would be to produce it as a glass ceramic with an optimum dispersion of a crystalline phase in the amorphous matrix so that crack deflection at and around crystals occur which would toughen bioactive glass ceramic by increasing the crack length. Partially crystallized bioactive glass therefore is a prime contender in the fabrication of a glass ceramic with improved fracture resistance. However, during crystallization it was observed that flowery patterns were produced inside the samples which upon analysis revealed to be inter-linked voids formed at the grain boundaries. These voids were formed as a result of shrinkage upon crystallization and may play influential part in the crack propagation behaviour in crystallized bioactive glass.