Disrupting environmental challenges leads to sustainable development endeavor not only in renewable energy but also in resource materials such as polymer nanocomposite materials which are finding increased applications in various engineering fields. However, manufacturing of nanocomposites involved energy intensive curing process which hampers towards sustainability. Hence, to address such issue understanding of thermal influence on the curing process is crucial. Therefore, the aim of this research is to identify the effective curing temperature and its influence that address the interfacial bonding characteristics through mechanical characteristics i.e. surface hardness. Five different samples were prepared to analyse the thermal effect of curing process via varying five different curing temperature. The surface hardness and morphological properties of glass fiber reinforced epoxy nanocomposites were analysed through microhardness and micrography analysis. It is revealed that mechanical characteristics of the nanocomposite significantly depends on the curing temperature of the specimen and beyond an effective curing temperature, would lead to degradation in mechanical performance with severe damages to the glass fiber and the resin. It is expected such findings would pave the way towards sustainable composite manufacturing technology.