A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt. %, more preferably 0.001-0.010 wt. %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-0.10. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt. % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO2. An embodiment of the invention covers a glass made according to the method.