Transparent glass ceramics (TGC) used in radioactive condition should exhibit different characteristics from pure glass and pure ceramic. Boroaluminosilicate TGCs containing gahnite nanocrystallite were synthesized and irradiated with various dose of gamma ray and were comparatively characterized in structure and property. Phase and network microstructural analysis reveal nonlinear evolution of crystalline phase in addition to incidental improved network connectivity of the residual glass phase, which agree well with the derived parabolic relation with gamma dose based on thermal spike and crystallization kinetics models. Consequently, irradiation induced optical absorption of the TGC is lower than the precursor glass despite optical contribution of Ti4+ photoreduction. The variation of optical as well as mechanical properties upon irradiation reaches an extremum at certain dose followed by reversal to saturation at higher dose and is consistent with the nonlinear structural modification as a function of gamma ray dose.