and mechanical properties of the polymeric system are studied.

MD simulations are performed by using the LAMMPS [@Plimpton_1995; @lammps]. The polymeric system is first equilibrated in the melted, liquid state at a temperature $T=1.0$. Further, the system is cooled down under a fixed pressure condition of [$P =0$]{} and with a cooling rate of $dT/dt = 10^{-4}$. During the cooling process, the glass transition occurs at a particular temperature, i.e., the glass transition temperature. After the glass transition, the system is quenched down towards the zero temperature, i.e., $T=0$ state.

![\[fig1\] [Glass transition temperature and density in the glass state.]{} (a) The specific volume $v$ versus the temperature $T$ during the process that the system is cooled down from the liquid state to the glass state. The color of line indicates the value of bending rigidity $\varepsilon_\mathrm{bend}$ according to the color bar. (b) Glass transition temperature $T_g$ (triangles) and density $\rho$ at zero temperature after the glass transition (circles) are plotted against $\varepsilon_\mathrm{bend}$. The chain length is $L=50$. ](fig1.pdf){width="48.00000%"}

![\[fig2\] [Conformation of polymeric chains.]{} (a) Probability distribution of angle formed by three consecutive beads along the chain, $P(\theta)$, is presented for several different rigidities $\varepsilon_\mathrm{bend}$. The color of line indicates 