Large Glass Shells from GDP Shells

An entirely new process was discovered starting from M-doped glow discharge polymer (GDP) deposited by plasma polymerization¹ (where M = Si or Ti) to make M-oxide shells. This process utilizing Si-GDP was developed to make large, uniform, thick-walled glass shells which are suitable for use in cryogenic layering experiments at LLNL and are unobtainable by the routinely utilized drop-tower method. We have found that in addition to controlling the geometry, the permeability and opacity may be controllable over very wide ranges by varying the processing conditions. Preliminary tests to determine the strength of SiO₂ glass shells made by this process are consistent with that expected of pure silica glass.