Optical rotation is the phenomenon where the plane of polarization of linearly polarized light rotates as it passes through an optically active substance.
Key Points:
- Occurs in chiral substances—molecules that are non-superimposable on their mirror images (e.g., sugars, amino acids).
- The amount of rotation depends on:
- The concentration of the substance.
- The path length of light through the material.
- The specific rotation of the substance.
- The wavelength of light used.
- The temperature.
Types:
- Dextrorotatory (+): rotates light clockwise.
- Levorotatory (–): rotates light counterclockwise.
Applications:
- Widely used in chemistry and biochemistry to identify chiral compounds.
- Employed in polarimeters for measuring concentrations of optically active substances in solutions (e.g., sugar solutions in food industry).