AbstractThe viscoelastic behaviour of polyether‐based polyurethane networks containing sodium tetraphenylborate was investigated by means of dynamic mechanical measurements. A quantitative analysis of the storage modulus dependence on temperature, frequency, and salt concentration gives rise to three superposition correlations, viz. frequency‐temperature, frequency‐concentration, and concentration‐temperature. The frequency‐temperature superposition follows a WLF behaviour, while the other two are approximately linear expressions particularly well verified in the zone of the transit