Tuneable Nanostructuring of Highly Transparent Zinc Gallogermanate Glasses and Glass‐Ceramics

New nanostructured gallogermanate‐based glass materials exhibiting high transparency in the visible and infrared regions are fabricated by conventional melt‐quenching. These materials can accommodate wide oxide compositions and present nanoscale phase separation, in the form of droplets well separated from the germanate matrix. The size of the nanostructures can be tailored depending on the composition. A single heat treatment then allows selective crystallization of the sole glassy phase corresponding to the droplets. As the crystal growth is limited by the size of the initial phase separation, the resulting glass‐ceramic materials exhibit nanostructures and transparency similar to the ones observed in the parent glass. The large variety of accessible compositions combined with the precise control over the nanostructure offer a great opportunity to design new highly transparent nanostructured glass and glass‐ceramic materials with a wide range of tuneable optical properties.