https://doi.org/10.1351/goldbook.15281
Polymer composed of macromolecules containing glutarimide rings in the backbone:
where \(\ce{R}\) is hydrogen or alkyl (usually methyl) and \(\ce{R^1}\) is hydrogen, or an alkyl, aryl, or heteroaryl group.



Note: A polyglutarimide is commonly prepared by modification of a poly(alkyl acrylate) with an amine, such as aniline, so it also contains residual acrylic units: 
