B2O3 is a prototypical glass forming oxide material and is an essential component in many industrial glasses. Unlike SiO2 and GeO2 its structure under ambient conditions is not based on tetrahedral units but is instead based on corner shared BO3 planar triangles. The network topology of B2O3 is, therefore, very different and there has been much debate on the role played by B3O9 boroxol rings which are planar motifs formed by connecting three corner-sharing BO3 triangles. The object of this proposal is to use neutron diffraction to measure the structure of B2O3 glass at pressures up to 15 GPa. The information thus provided will extend the maximum pressure at which B2O3 glass has been investigated by in situ diffraction methods from 9.5 GPa to 15 GPa and will be used to help elucidate the nature of the network collapse as the mean coordination number of B changes from 3 to 4.