Refractive Index of Acrylic, Acrylate, Lucite, Perspex, Plexiglass

Acrylic was one of the earliest polymers to be commercialized. Most acrylates are variations of poly(methylmethacrylate) with the repeating formula of (C5O2H8)n. Lucite, Perspex, Plexiglass (and many others) are all product brand names for this material. Uses include a wide variety of transparent coverings (both protective and decorative), e-beam photoresists and a plethora of medical applications. It is often used as a glass replacement and conveniently its refractive indices are relatively close to those of glass. No longer considered a cutting edge material, acrylic is still a preferred option where moderate properties and lower costs are required. Its optical performance can be enhanced by applying scratch-resistant, SiO2-based, thin films. Sometimes these are referred to as "hardcoats".

While acrylic’s refractive index is usually close to the values reported below, this can be adjusted by copolymerization with other monomers. Fluoroacrylate monomers can lower the index. Conversely, incorporating monomers that contain nitrogen or bromine can increase its index of refraction. More recently acrylic has benefited from improved cache as it does not contain the purportedly-harmful bisphenol-A monomer.

For a typical sample of Acrylic the refractive index and extinction coefficient at 632.8 nm are 1.48899 and 0. Below are files of complete refractive index and extinction coefficients. If the file is not available for download, you can request our proprietary file by clicking "Request".

Refractive Index Reference - S. N. Kasarova et al. (2007) Analysis of the dispersion of optical plastic materials, Optical Materials 29, 1481-1490

No guarantee of accuracy - use at your own risk.