Measurements of low temperature specific heat C-p (1.5 K-25 K) have been carried out in AgI-Ag2O-B2O3 superionic glasses. It has been revealed that modifications of the network coherence change the magnitude of the hump in the specific heat, which is observed when it is plotted as C-p/T-3 : the increasing connectivity (defined as the number of bridging bonds per network forming ion) reduces the deviations of C-p from a T-3 behavior. Finally comparative measurements of low temperature C-p and low frequency Raman scattering (below 100 cm(-1)) in the same glass permit us to assess the frequency dependence of the photon-vibration coupling coefficient C(omega) and the spectral density of low-energy vibrational modes g(omega).