Poly(glycolide) polymers are disclosed. The polymers generally include a glycolide-based polymer backbone that includes one or more functional groups such as alkynyl groups, hydrophilic organic triazole groups, hydrophobic organic triazole groups (also including amphiphilic organic triazole groups), di-triazole organic crosslinking groups, and triazole-substituted drug derivatives. The alkynyl groups provide reactive sites for further functionalization of the polymer, for example by reaction with azide derivatives. The polymers can further encapsulate a drug for delivery to a patient (i.e., as compared to drug derivatives that are covalently attached to the polymer). The polymers can be in the form of thermodynamically stable unimolecular micelles or crosslinked nanoparticles. The polymer compositions are completely biodegradable and hold great potential for use in biomedical applications.