Formation and destruction of silicon hydride (Si–H) groups in silica by F 2 laser irradiation and their vacuum ultraviolet (VUV) optical absorption was examined by infrared (IR) and VUV spectroscopy. Photoinduced creation of Si–H groups in H 2 -impregnated oxygen deficient silica is accompanied by a growth of infrared absorption band at 2250cm −1 and by a strong increase of VUV transmission at 7.9eV. Photolysis of Si–H groups by 7.9eV photons in this glass was not detected when the irradiation was performed at temperature 80K. However, a slight destruction of Si–H groups under 7.9eV irradiation was observed at the room temperature. This finding gives a tentative estimate of VUV absorption cross section of Si–H groups at 7.9eV as 4×10 −21 cm 2 , showing that Si–H groups do not strongly contribute to the absorption at the VUV fundamental absorption edge of silica glass.