Photosensitive glasses and glass ceramics and composite glass materials made therefrom

A strengthened composite glass article comprising

• a first region and a second region in contact with the first region at an interface,
• the first region comprising a lithium-based glass ceramic, the lithium-based glass ceramic comprising a ceramic phase and a residual glass phase, wherein the ceramic phase comprises a lithium aluminosilicate phase having a lithium aluminosilicate stuffed β-quartz structure, and
• the second region comprising a lithium zinc aluminosilicate glass, wherein the lithium zinc aluminosilicate glass is transparent and comprises at least one sensitizing agent and at least one nucleating agent
• wherein the lithium zinc aluminosilicate glass is in tension and the lithium-based glass ceramic is in compression at the interface to produce a crack propagation region.