The pellets were thermally treated under vacuum, at different Tw values over Tg, but without exceeding the Tr of the inorganic glass (Fig. ). The optimal conditions were found with 0.22 GPa during the pelletisation before isothermal heating at 310 °C (Tw) for 30 min. At this pressure, the Bragg intensities of the crystalline component (ZIF-8) are maintained, and a bulk robust pellet is formed (Fig. ).