Oxygen induction time (OIT)
A relative measure of a level or a degree of stabilisation (amount of remaining active antioxidant).

Optical properties
Optical properties are important in packaging applications where decorative printing is required or good visibility of the packed product is essential. Gloss and haze are used to characterize optical appearance of film products.

Optical Microscopy
Optical Microscopy (OM) is usually the most familiar tool to study material morphology and it offers many techniques for polymer characterisation including transmission, reflected light, dark field, polarized light, phase contrast and interference contrast microscopy. These techniques give information based upon the variations in light scattering, differences in refractive index and differential phase shifts of reflected or transmitted light. Light microscopy indicates the physical aspects of polymer composition, such as multiple phases present, the sizes and shapes of the particles and overall characteristics of the individual particles.