The Social Network Analysis (SNA) techniques allow modelling and analysing the interaction among individuals based on their attributes and relationships. This approach has been used by several researchers in order to measure the social processes in collaborative learning experiences. But oftentimes such measures were calculated at the final state of experiences, what may be hardly representative of students' behaviours during the learning processes. Therefore, a temporal dimension in SNA metrics may extend and improve the understanding about students' interactions in a collaborative scenario. In this respect, this paper presents a systematic review about SNA metrics used for analysing CSCL scenarios and proposes to trace the behaviour of such metrics during experiences through the inclusion of a temporal dimension. In order to expose this approach, a real collaborative learning experience, supported by a platform called SMLearning System, was analysed. We found that social relationships among students tend to be symmetric, i.e., there was a proportional distribution of efforts and contributions of students, which is an expected condition in a collaborative scenario. Such observations are based on the temporal behaviour of the reciprocity metric and the correlation between in- and out-degree centrality metrics measured in time.