Static and dynamical properties of a model glass-forming oligomer liquid are analyzed using molecular dynamics simulations. The temperature and system size effects are assessed for the affine shear modulus μA, the quasistatic shear modulus μsf (obtained using the stress-fluctuation relation), and the shear relaxation modulus G(t). It is found that while both μA and μsf are nearly independent of the system size, their variances show significant system size dependence, in particular, below the glass transition temperature Tg. It is also shown that the standard deviation of the shear modulus, δμsf(T), exhibits a pronounced peak at TTg whose position is nearly independent of the system volume V. Moreover, the whole function δμsf(T) is nearly the same for different system sizes above the glass transition. We propose a theory which quantitatively predicts δμsf(T) at TTg and explains both its independence of V and its peak near Tg. It is also established that below Tg the variance of the affine modulus follows the standard power law, δμA21/V, while δμsf shows anomalously a slow decrease with V as δμsf21/Vα with α < 1. On this basis, it is argued that the studied glass-forming systems must show long-range structural correlations in the amorphous state.

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