Pressure-induced densification in GeO2 glass: A transmission x-ray microscopy study

Nanoscale transmission x-ray microscopy measurements have been performed to determine the effect of pressure (P) on the volume (V) change in GeO2 glass up to 38.5 GPa. The P-V data show a continuous increase upon compression, indicating that the density-driven structural transformation is a gradual process. Over the pressure range studied, a transition is observed at approximately 10-13 GPa, where the material displays distinct compression behaviors. The pressure-induced densification that involves the coordination number change has been discussed. Using this newly developed high-pressure imaging technique with tens of nanometer resolution, we have provided a direct and unequivocal way for measuring density of amorphous materials to much higher pressures with accuracy rivaling x-ray diffraction of crystalline solids. (C) 2013 AIP Publishing LLC.