Refractive Index - ASTM D542 Plastic Test Standard

Refractive Index - ASTM D542

Refractive index, or index of refraction, is the ratio of the velocity of light in a vacuum to its velocity in the material in question. Refractive index is useful for identifying materials, and is important in optical applications.
Testing for ASTM D542 is performed using an Abbé refractometer.

Index of refraction can be calculated using Snell's Law:
n₁ / n₂ = sin θ₂ / sin θ₁
where n₁ and n₂ are the refractive indices of mediums 1 and 2, θ₁ is the angle of incidence, and θ₂ is the angle of refraction.

Refractive Index Geometry

Similar Standards

• ISO 489

Property information for specific grades of resin are available in the Prospector Plastics Database.