Transition metal borides (TMBs) represent a highly promising family of materials for functional coatings due to their abundance, cost-effectiveness, and exceptional mechanical properties. These include a high melting point, hardness of up to 60 GPa, excellent chemical and thermal conductivity, and outstanding resistance to wear. TMBs exhibit unique self-lubricating properties by forming boron oxide layers, reducing friction. The prevalent temperature strongly influences the formation of boron oxide. However, the fundamental mechanisms of this tribo-reaction are still not fully understood, particularly for TMB-based thin film materials. Therefore, a detailed knowledge of the oxidation behavior of physical vapor deposited TiB2 thin films is crucial for understanding their friction and wear properties. Tribological tests reveal that sputter deposited super-stoichiometric TiB3.5 exhibits a significantly lower friction coefficient (~0.25), roughly half compared to that of sub-stoichiometric TiB1.67, tested at 500°C. This reduction is attributed to the higher oxidation rate of super-stoichiometric TiB3.5 and the presence of B-rich tissue phases at the column boundaries. Furthermore, we conduct an in-situ investigation of the oxidation process in sub- and super-stoichiometric TiB2±z thin films using time-of-flight elastic recoil detection analysis (ToF-ERDA). This technique provides detailed depth profiles of the chemical composition over a temperature range from room temperature to 600°C. The oxidation data are further correlated with tribological, XRD, and TEM analyses, offering novel insights into the lubrication mechanisms of boron oxide in TMB thin films across a wide temperature range.