Modern industrial development processes of new technologies are characterized by an increasing complexity and interdependence of different actors combining different knowledge assets. Today, hardly any innovation can be assigned to a specific technological field. Also, the sciences are becoming increasingly differentiated and specialized, thus enhancing the necessity of horizontal and vertical knowledge transfer between the actors of innovation processes. In this context, where single actors and even single firms are unable to keep pace with technological progress, the access to external knowledge sources via informal know-how exchange networks increasingly gains in importance. In the paper a synergetic modelling framework of the evolution of informal networks is combined with time patterns of the industrial evolution sketched by the theory of industry life cycles. Integrating timeindependent transition rates excludes the possibility of analytical solutions, so numerical simulation experiments have to be performed. The results of these experiments show structural developments at least qualitatively according to the predictions of life cycle theory. Most unexpectedly - from a traditional point of view - large informal networks as a potential source of technological spillovers can be observed in a state of the industry life cycle where R&D endeavours of firms are assumed to be already concentrated on exploiting scale economies and process technologies and where intuitively a strategy of keeping new know-how secret would be expected.
