Polar Liquid Crystal Elastomers Cross Linked Far from Thermodynamic Phase Transitions: Dislocation Loops in Smectic Clusters

Figure 6

The optical birefringence, Δ𝑛 versus 𝜆, shows a monotonic increase in orientational order for CN50, CN70, and CN100. The symbols show the 𝜆 data points from Figure 5. As 𝜆→1, Δ𝑛 is linear in 𝜆 (dashed lines) in all samples up to the value of 𝜆 at 𝑇^∗ (highlighted by arrows) in CN70 and CN100. The deviation from linearity in CN50 is below 𝑇^∗. In CN70, Δ𝑛 departs from saturation type behavior at large 𝜆 in the proximity of an estimated glass transition at 𝑇_𝑔≃17--20^∘C.