In this thesis fluorescent europium (Eu)- and barium chloride (BaCl2)-doped fluorozirconate (FZ) based glasses and glass ceramics, which are known for their efficient scintillation and storage phosphor properties, were the subject of improvement going along with their structural and optical investigation. One main focus is the investigation and optimization of the Eu valency. The addition of indium to the glass host improves glass quality and is also needed for a phase transformation from hexagonal to orthorhombic phase BaCl2 nanoparticles, which is important for storage phosphor applications. Subsequent remelting of the glass proves to increase the Eu2+content and thus the performance of the glass ceramics for scintillator applications. Additional co-doping with other trivalent rare earths, namely Gd, Nd, Yb, or Tb, for light output enhancement influences the nanocrystal nucleation and growth as well as the Eu2+photoluminescence.