Objectives: To determine the effect of heat on flexural strength (FS), maximum strain (MS), storage modulus (SM), tan delta (TD) and chemical changes through micro-Raman spectroscopy of dentine exposed to 2.5% NaOCl or saline. Methodology: Dentine bars were randomly allocated to 8 test groups. Half (groups 2,4,6,8) were treated with NaOCl for 20 mins; the rest (groups 1,3,5,7) remained in saline. FS/MS were measured in groups 1-4 (n=15) (3/4 were also heated to 200°C & re-hydrated in saline). Micro-Raman spectroscopy was performed on bars from groups 1-4. SM/TD were measured in 5-8: in 5/6 (n=10), repeated after heating (200°C), then following re-hydration; in 7/8 (n=3) after heating to 25−185°C. Results: Increase in MS on heat and FS/MS on heat+NaOCl was not significant (P>0.05). SM increased (P=0.06) after heat treatment but reduced to initial state after rehydration (P=0.03). TD did not change (P=0.4) after heat (200°C) treatment but rehydration increased it compared with pre-treatment state (P=0.001). For dentine bars pre-treated with NaOCl, SM did not change (P=0.6) after heat (200°C) treatment or rehydration but TD significantly increased (P=0.02) upon re-hydration compared with pre-(P=0.007), or post-(P=0.03) heattreatment states. SM and TD varied between 25−185°C with no consistent trend amongst the NaOCl pre-treated bars. Micro-Raman only detected chemical changes following NaOCl treatment in the mineral phase. Conclusions: Exposure of dentine bars to heat and NaOCl produced only moderate changes to quasi-static but marked changes to viscoelastic properties, which may be explained by chemical alterations.