The effects of a poor initial estimate for the time constant using the two-dashpot Kelvin model. The solid line is the curve fit for initial curve fit with the resulting parameters: A0 = 1499 × 103, A1 = 195.8 × 103, τ1 = 1.248, A2=429.1 × 103, τ2 = 20.6. The dashed line is the fit for a 10% higher initial estimate for τ2, resulting in A0 = 1499 × 103, A1 = 421.6 × 103, τ1 = 17.1, A2= 173.3 × 103, τ2 = 2.2 × 10−14. The poor fit from these parameters was evident in the initial part of the curve. The other models were not sensitive to the initial estimates within the range tested.