The sintering behavior of a glass-ceramic (commercial material Ceramtape GC) was characterized using the discontinuous sinter-forging technique. The uniaxial viscosity E-p and the viscous Poisson's ratio n(p) of the composite body were determined as a function of density. Particular attention was paid to microstructural changes in order to quantify the anisotropy induced by load application. Pores and alumina particles were found to be both oriented perpendicular to the applied load direction. Finally, the experimental results were used to predict the value of the hydrostatic sintering stress.