A Novel Iterative-Fitting Approach for the Thermal Characterization of Thin Fibers

Abstract

The transient electrothermal technique (TET) is widely used to measure the thermal properties of thin fibers and films, but its accuracy declines when radiative heat losses are significant and surface emissivity is unknown. These conditions are difficult to avoid at the microscale, while conventional analyses either neglect them or rely on separate measurements that introduce sequential errors. We present a TET implementation that determines multiple thermal properties and effective surface emissivity from only two transient measurements. An analytical model incorporating thermal radiation and variable heat generation supports sensitivity-guided, multiparameter fitting. Two forms of the temperature solution yield thermal conductivity and diffusivity, and thermal conductivity and volumetric heat capacity, respectively. An iterative fitting procedure then recovers intrinsic properties corrected for environmental effects while reducing the required sample count and measurement time. Measurements of amorphous silicon dioxide (SiO2) optical fiber and Hi-Nicalon Type S silicon carbide (SiC) fiber agreed with literature values to within an average error of approximately 10% across all samples. Experimental and numerical uncertainty analyses quantify measurement variability and relate it to sample geometry. This method simultaneously resolves multiple intrinsic thermal properties, corrects radiative-loss errors, and provides quantitative guidance for sample geometry selection.