A new long-term indentation relaxation method to measure creep properties at the micro-scale with application to fused silica and PMMA

•A new indentation relaxation experiment based on the control of the contact stiffness is developed.•The proposed methodology allows for long-term measurements of material’s creep properties without any thermal drift issues.•Creep parameters are extracted from a Bingham Norton viscoplastic model at very low strain rates, down to 10−8 s−1.•Results obtained on fused silica and PMMA highlight the ability of the proposed method to measure quantitative creep properties on a broad range of strain rates.