TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Process: The bubbling of the oxidizing gas is performed during the cooling step; and after the refining step. In the process, the amount of oxidizing gas bubbled in the glass melt is such that the total quantity of oxygen introduced into the glass melt is 0.01-20 l/kg of glass, preferably 0.1-5 l/kg of glass. The process comprises bubbling the oxidizing gas by at least one metal component pierced by holes; and bubbling oxidizing gas by at least one component made of porous refractory ceramic. Preferred Components: The oxidizing gas is oxygen. The bubbling creates bubbles in the glass melt that has an average diameter of 0.05-5 cm, preferably 1-2 cm. The viscosity of the glass during bubbling is 100-1000 poise, preferably 300-600 poise. The glass contains more than 50 wt.%, preferably 60 wt.% of silica. The glass has a redox of greater than or equal to 0.1, preferably 0.08-0.05. The glass contains a total content of iron oxide of less than or equal to 0.15 mass%, preferably 0.02-0.01 mass%. The glass is a glass-ceramic precursor of colorless lithium aluminosilicate, and at least one reducing agent, which is added to raw materials, preferably associated with a sulfate. The reducing agent is coke or metal sulfides, including zinc sulfide. The glass temperature during bubbling is 1550-1650 degrees C. The substrate comprises total content of iron oxide of: less than or equal to 0.02 wt.%, preferably 0.009%; or greater than 0.02%, preferably less than or equal to 0.15%. The quantity of oxygen bubbles is 500-10000 bubbles per liter of glass. EXAMPLE - Primary material comprising silica (68.6 wt.%), aluminum oxide (19.5 wt.%), ferric oxide (0.017%), lithium oxide (3.6 wt.%), zinc oxide (1.8 wt.%), magnesium oxide (1.2 wt.%), barium oxide (0.8 wt.%), titanium dioxide (2.7 wt.%), zirconium oxide (1.7 wt.%) was introduced in an oven at a fusion temperature of 1600-1650 degrees C and worked up to obtain colorless glass ceramic of lithium aluminosilicate.