Poly(lactide-co-glycolide) (PLGA) is a widely used biodegradable copolymer in

biomedical and other applications. During processing and service, PLGA-based

materials are frequently subjected to deformation and mechanical loading. However,

the stretch-induced structural evolutions of PLGA remain poorly understood. Herein,

we investigated the multiscale structural evolutions of PLGA copolymers with

different glycolic acid (GA) contents during uniaxial stretching using synchrotron-radiation

wide and small-angle X-ray scattering. Compared with poly(lactic acid) (PLA)

homopolymer, PLGA copolymers exhibit lower crystallinity and a bimodal

crystalline population consisting of conventional PLA α crystals and defect

crystals with GA comonomer inclusion. During stretching, both PLA and PLGA

undergo sequential crystal twinning, fragmentation, melting, and eventually

chain orientation along the stretching direction. Notably, the defect crystals of

PLGA preferentially disintegrate at small strains yet are regenerated at large

strains through strain-induced recrystallization. Increasing GA content reduces

the crystallinity, thereby delaying crystal fragmentation and suppressing

cavitation. Elevating the stretching temperature enhances chain mobility,

mitigates crystal fragmentation and lattice strain, and promotes strain-induced

recrystallization. This study is helpful for understanding the deformation mechanism

of PLGA-based materials and provide guidance for tailoring the processing and

mechanical performance of random copolyesters.