Methods for producing glass articles of a wide range of geometrical shapes, including shapes that are heretofore difficult or impossible to make monolithically. The glass articles are made by first building the nascent glass article from glass powder and a binder using a three-dimensional printing free-form fabrication process followed by sintering the nascent glass article at a temperature that is hundreds of degrees above the glass powder composition's glass transition temperature while supporting the nascent glass article in a bed of an inert powder having a high flowability.