In the framework of the Megajoule Laser project driven by the French Atomic Energy Board, one of the most valuable optical programs in term of material volume as well as in term of component size, the actual glasses and production means appear to be inconsistent with the economical objectives. Corning proposed an alternative, based on the use of a low cost glass, together with an evolution of the production process. Combining its experience in quality optical glasses manufacturing and its mastery of forming processes, Corning conducted a production cost reduction program; the objective of this program was to validate the concept of large slab melting (about 2000 kg each), where blocks are cut off, versus the conventional single block (about 100 kg) melting. Economical improvements are based on a reduction of lost time (mold change) and production lead- time by increasing the feeding yield, on a better glass utilization, and a reduced number of molds. The technical issues were: increase the feeding yield maintaining a given glass quality level, reduce the glass allowance, improve the materials of the molds, reinforce the thermal process control, automatism of critical operations, especially at the start-up and at the end of the mold feeding. Despite the long production cycle, about 3 months including melting and annealing, the first results carry the technological options set-up.