Optical Properties Test

The optical properties of a substance mainly refer to the various properties of the substance when it absorbs, reflects and refracts light, as well as the phenomenon of light interference and scattering caused by the substance. Optical properties are one of the most important and commonly used properties of materials. The performance evaluation of thin films, ceramics, glass, powder, polymers, intraocular crystals and even colloids is inseparable from the characterization of optical properties.

Test Capabilities

• Refractive index

The refractive index is one of the most important physical constants of organic compounds. It can be measured accurately and conveniently. As a standard for the purity of liquid substances, it is more reliable than the boiling point. The refractive index can be used to identify unknown compounds and is also used to determine the composition of liquid mixtures.

• Dispersion coefficient

Dispersion coefficient indicates the degree of dispersion of light by the medium. It is usually expressed by Abbe number, so the dispersion coefficient is also called Abbe number, which determines the quality of the lens imaging. The larger the dispersion coefficient (Abbe number), the less obvious the dispersion and the better the imaging quality of the lens.

• Birefringence

Birefringence is usually quantified as the maximum difference in refractive index between materials. Our polymer scientists use polarized light to achieve birefringence, which can be used to quantify stress in transparent plastics.

• Reflection coefficient

Reflection coefficient refers to the ratio of the intensity of the reflected light on the surface to the intensity of the incident light when the light is projected on the object. It is affected by the projection angle, intensity and wavelength of the incident light, the properties of the material on the surface of the object and the measuring angle of the reflected light.

• Haze measurement

Haze is an objective measurement of the translucency of a material. A good quality surface should have a clear and bright appearance. The microstructure caused by the poor dispersion of the pigments of the paint will have a milky appearance.

• Glossiness

Gloss, as the surface characteristic of an object, depends on the specular reflection ability of the surface to light. The so-called specular reflection refers to a reflection phenomenon where the reflection angle is equal to the incident angle. Glossiness is a physical quantity that evaluates the ability of the surface of a material to reflect light under a set of geometrically prescribed conditions.

• Thermicity

Thermicity is the capacity of a greenhouse film to retain the heat that dissipates at night thus slowing down nocturnal heat losses and, consequently, reducing excessive drops in temperature inside a greenhouse, and preventing them from affecting the quality or viability of the crops.

• UV-visible light transmission

UV-visible light transmission is the ability of a plastic material to allow light to pass through it in the UV-visible range, measured by spectroscopy.

• Turbidity

Turbidity is associated with the light scattering produced by the accumulation of tiny particles within the material or by very small defects on the surface of materials.

• Colorimetry

Color measurements assess color changes induced by various stresses. The following characteristics of a sample are measured or calculated in an automatic spectral photometer

• Transmittance
• Reflectance
• Yellowness index
• L*a*b* values
• Standard color values XYZ
• Delta E
• Spectral analysis

• Gray scale determination

Gray scale determination identifies the optical surface change after different stress loads, such as processing, after-treatment, light aging, weathering and temperature aging.

Test Material Types

• Glass
• Ceramics
• Polymer

During production, various steps such as coloration, heat treatment and mechanical processing can affect optical properties, STEMart expertly analyses a range of optical properties, delivering accurate information to help you to optimize production in order to achieve optical property specifications. For more information about our optical properties testing, please contact us.