  We develop a simple coarse-grained bead-spring polymer model exhibiting
competing crystallization and glass transitions. For quench rates slower than
the critical nucleation rate $|\dot{T}|_{crit}$, systems exhibit a first-order
crystallization transition below a critical temperature $T=T_{cryst}$. Such
systems form close-packed crystallites of FCC and/or HCP order, separated by
domain walls, twin defects, and an amorphous interphase. The size of amorphous
regions grows continuously as the quench rate $|\dot{T}|$ increases, producing
nearly amorphous structure for $|\dot{T}|>|\dot{T}|_{crit}$. Our model exhibits
many features observed in recent studies of crystallization of athermal polymer
packings, but also critical differences arising from the softness of the pair
interactions and the thermal nature of the phase transition. The model is
considerably more computationally efficient than other recent crystallizable
coarse-grained polymer models; while it sacrifices some features of real
semicrystalline polymers (such as lamellar structure and chain
disentanglement), we anticipate that it will serve as a useful model for
studying generic features related to semicrystalline order in polymer solids.
