Optimization of holographic polymer dispersed liquid crystal for ternary monomers

Polarized optical micrography (POM) images of gratings and UV–visible spectra of holographic polymer dispersed liquid crystals (HPDLC) are reported for a ternary monomer system composed of dipentaerythritol hydroxypentaacrylate/trimethylolpropanetriacrylate/N‐vinylpyrrolidone (DPHPA/TMPTA/NVP) = 7/2/1 by weight. Gratings were written by irradiation with an argon ion laser (λ = 488 nm) at various intensities (20–200 mW cm⁻²) on monomer/liquid crystal (LC) composite films of various compositions (75/25, 70/30, 65/35, 62/38, 60/40). Reflection efficiency–irradiation intensity–film composition relationships are obtained in three dimensional plots which show that maximum reflection moves from high LC content (38%) at low irradiation intensity (20 mW cm⁻²) to low LC content (25 wt%) at high irradiation intensity (200 mW cm⁻²). © 1999 Society of Chemical Industry