Fig. 4

Time-dependent extracted fit coefficients for α-NIF (red markers) and β-NIF (blue markers) of initially amorphous NIF samples stored at (a) 24 °C, (b) 30 °C and (c) 35 °C. The grey error bars represent the standard deviation of the assessed fit coefficients of the five samples investigated per storage temperature. Every 4th measurement was evaluated, which corresponds to steps of approximately 14 min.