Observation of defects inscribed in 3D photonic band gap opal templates has been investigated by means of fluorescence of solidified photo polymer. The defects, or breaks in periodicity, have been inscribed inside the structure by two-photon polymerization (2PP) of an infiltrated hybrid polymer from the type ORMOCER®. In-situ and ex-situ observation of the inscribed defects has been achieved with fluorescence microscopy.