Architectural glass light in industrial factories. Annealed glass is glass without internal stresses caused by heat treatment, i.e., rapid cooling, or by toughening or heat strengthening. Glass becomes annealed if it is heated above a transition point then allowed to cool slowly, without being quenched. Float glass is annealed during the process of manufacture. However, most toughened glass is made from float glass that has been specially heat-treated. Annealed glass breaks into large, jagged shards that can cause serious injury and is considered a hazard in architectural applications. Building codes in many parts of the world restrict the use of annealed glass
Venetian glass the layering of colored liquid glass, heated to , which is then stretched into long rods called canes. When cooled, these canes are then sliced in cross-sections, which reveals the layered pattern. Ercole Barovier, a descendent of Murano's greatest glassmaker Angelo Barovier, won numerous awards during the 1940s and 1950s for his innovations using the murrine technique. "Sommerso" ("submerged" in Italian), is a form of artistic Murano glass that has layers of contrasting colors (typically two), which are formed by dipping colored glass into another molten glass and then blowing the combination into a desired shape. The outermost layer, or