Transitions into liquid crystalline phases may be stimulated either by changes in temperature (thermotropic liquid crystals) or concentration (lyotropic liquid crystals). Polybenzyl L-glutamate (PBLG) is an example of a lyotropic liquid crystal that develops stiff helical rods in many organic solvents. These rods have often been observed to exhibit a cholesteric ordering. Similar to other substances that exhibit cholesteric phases, PBLG solutions experience a modulating refractive index due to the Bragg scattering of various colors of light caused by the helical organization of the liquid crystals.