the value of bending rigidity $\varepsilon_\mathrm{bend}$ according to the color bar. (b) Radius of inertia $R_g$ is plotted as a function of $\varepsilon_\mathrm{bend}$. The chain length is $L=50$. ](fig2.pdf){width="48.00000%"}

![image](fig3.pdf){width="96.00000%"}

Results
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Glass transition temperature
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When the polymeric system is cooled down from the liquid state under a constant pressure, the volume of the system monotonically decreases with decreasing the temperature. Figure \[fig1\]a shows the specific volume $v$ as a function of the temperature $T$ for several different bending rigidities $\varepsilon_\mathrm{bend}$ and the chain length $L=50$. For each value of $\varepsilon_\mathrm{bend}$, the slope of the $v$-$T$ curve clearly presents a discontinuous change at a certain temperature, which is defined as the glass transition temperature $T_g$. Figure \[fig1\]b (triangles) presents the value of $T_g$ as a function of $\varepsilon_\mathrm{bend}$. As the rigidity increases from $\varepsilon_\mathrm{bend} = 1$ to $10^3$, $T_g$ progressively increases from $T_g \simeq 0.45$ to $0.75$. Below $\varepsilon = 1$ and above $\varepsilon = 10^3$, the variation of $T_g$ is low or even negligible. In addition, Figure \[fig1\]b (circles) plots the density $\rho(=1/v)$ of the system that is quenched down to $T=0$. The density decreases from $\rho \simeq 1.09$ to $0.97$ as the rigidity increases from $\varepsilon_\mathrm{bend} =1$ 