This report is the first describing a letter of pressure-induced condensation of silanol. Raman and infrared absorption spectra of trimethylsilanol were observed at room temperature and at pressures up to 3.3 GPa. After solidification at 0.3 GPa, the OH vibration mode shifted to lower frequencies along with increasing pressure with a notably large pressure coefficient (-107 cm(-1)/GPa), thereby indicating that hydrogen bonding in trimethylsilanol had strengthened prominently. Along with increased hydrogen-bond interaction, condensation of trimethylsilanol forming hexamethyldisiloxane and molecular water were observed. The marked shift in the OH stretching mode in the released H2O suggests considerable intermolecular interaction with hexamethyldisiloxane. (C) 2013 Elsevier B.V. All rights reserved.