This paper investigates the accuracy of the step-wise transient (SWT) method and proposes a modified model that embodies the real-world experimental setup. The presented model incorporates all the imperfections of the thermocouple and heater, such as the thermal capacity and thermal contact resistance with the specimen. The viability of the proposed hypothesis was confirmed via the experiment simulation for soda-lime-silica glass material. The total uncertainty of the thermal conductivity and diffusivity measurement was assessed by combining all the associated errors: model, random, and measurement errors in input parameters. The scope of this work concentrates on one particular material, which can be potentially used as a reference material for calibrating other characterization methods. The results of thermal conductivity and diffusivity were λ = 1.017 W·m⁻¹·K⁻¹ and a = 0.507 mm²·s⁻¹ with total standard uncertainties 0.6 % and 0.4 %, respectively.

本文研究了逐步瞬变（SWT）方法的准确性，并提出了一个包含实际实验设置的改进模型。提出的模型包含了热电偶和加热器的所有缺陷，例如样品的热容量和热接触电阻。通过对钠钙硅玻璃材料的实验仿真，证实了所提出假设的可行性。通过综合所有相关误差：输入参数中的模型误差，随机误差和测量误差，评估了热导率和扩散率测量的总不确定度。这项工作的范围集中在一种特定的材料上，该材料可以潜在地用作校准其他表征方法的参考材料。导热系数和扩散系数的结果是λ  = 1.017 W·m ^-1 ·K ^-1和a  = 0.507 mm ² ·s ^-1，总标准不确定度分别为0.6％和0.4％。