I also reversed the plots to Stress vs. birefringence for better visualization.

Formula 1: Arylamide (There was a slight issue of this hydrogel slipping during measurement end)

Fig 1: Stress vs Retardation 

Fig 2: Stress vs. Diattenuation 

Formula 2: Di-phenyl

Fig 3: Stress vs Retardation 

Fig 4: Stress vs. Diattenuation