what is organic glass? what is its composition? it doesn't seem to have a universal meaning, and there are some commercial products that call themselves organic glass.
There shouldn't be much silicon in a brain, so is the organic glass a mostly carbon substance? almost like coal?
The elemental analysis (in the supplemental info linked at the end of the original article) shows carbon and oxygen plus trace elements (and presumably hydrogen, which SEM dispersive X-ray analysis doesn't detect). So it could be an amorphous polymer, such as polycarbonate. They didn't do any molecular analysis.