Membranes of chitosan (CTS) and composite membranes of CTS with Bioglass® were prepared by solvent casting. Composite membranes were shown to induce the precipitation of apatite upon immersion in simulated body fluids (SBF). The biomineralization process was followed by measuring the variation of the viscoelastic properties of the membranes immersed in SBF, both online and offline. Non-conventional dynamic mechanical analysis was used to measure the change in the storage modulus, E’, and the loss factor, tan δ, as a function of the immersion in SBF. A simple model was used to estimate the E’ of the apatite layer formed in-vitro that was about 130 MPa. This work showed that innovate mechanical tests could be useful to characterize the mechanical performance of composites under physiological conditions.