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Laminated Glass - Laminated (or compound) glass consists of two or more sheets of glass with one or more viscous plastic layers "sandwiched" between the glass panes. The solid joining of the glass takes place in a pressurized vessel called an autoclave. In the autoclave, under simultaneous heating of the already processed layers of glass and special plastic, lamination occurs. When laminated safety glass breaks, the pieces remain attached to the internal plastic layer and the glass remains transparent.

Lampworking - Flame re-working of a blank or tubing cane, typically on a lathe.

Latticino - Cane that gives the appearance of lattice.

Lear - A gigantic oven that is computer-controlled to relieve stress during the annealing process.

Lehr - A long belt-fed, tunnel-shaped oven used to heat glass to the annealing point and then slowly cool it to room temperature to remove any residual thermal stresses in the glass. Can also be a large oven where glass is manually loaded and unloaded (batch lehr).

Linear Coefficient of Expansion - The fractional change in length of a piece of glass per degree change in temperature. The coefficient of expansion generally indicates the thermal endurance of the glass. Glasses with a low linear coefficient of expansion can be subjected to greater rapid temperature changes with less chance of fracture than glasses with a high coefficient of expansion. (Generally, Type I glasses have a lower COE than Type III).

Lost Wax Casting - The object to be fashioned in glass is melded in wax and encased in clay or plaster that is heated. The wax melts or is "lost" , leaving a mold into which hot glass can then be poured. The mold must be broken in order to retrieve the cast object.