Abstract: An untempered sheet of glass is given a predetermined curvature by means of pre-heated forming dies (3,4 in FIG. 1). The glass sheet (1) is not pre-heated or is heated only to a relatively low temperature prior to being inserted between the dies. Heat transfer from the dies to the glass prior to closure of the dies produces or assists in producing in the thickness of the glass sheet a transitory thermal stress gradient which gives resistance to breakage under bending forces. The absence of high temperature pre-heating of the sheet is conducive to a more predictable stress distribution pattern over the area of the sheet prior to bending. The process enables predetermined sheet curvatures to be achieved with higher degrees of accuracy.