Lead-free glasses of the heavy flint optical layer, their use and processes for their preparation

Optical glass, characterized in that it comprises the following composition (in wt .-% based on oxide): P 14-35 Nb 45 - 50 Li 0-4 Na 0-4 K 0.5 to 5 BaO 17-23 ZnO 0.1 to 5 TiO 1 - <5 ZrO 0-6 Sb 0.1 to 2