Mn
2C-doped GeO 2 -B 2 O 3 -ZnO (GBZ) glasses were investigated and developed as long-lasting phosphorescence host materials. Transparent glass-ceramics were obtained after heat-treated at the first crystallization temperature for 20 min. By X-ray diffraction measurement and SEM observation, it is clarified that Zn 2 GeO 4 crystallites with a diameter of about 1 mm precipitate on the sample's surface after heat-treatment. An orange long-lasting phosphorescence from Mn 2C was observed in the 25GeO 2 -25B 2 O 3 -50ZnO glass matrix, however, a stronger long-lasting green phosphorescence was observed in the phase of Zn 2 GeO 4 crystallites. This phenomenon is considered to be due to the different ligand field environment surrounding Mn 2C ions in the glass and the glass-ceramics. A possible mechanism for the long-lasting phosphorescence in the Mn 2C -doped glass was discussed.