Haze measurements

Transmission and Haze Measurements. Light transmission measurements were made with a Gardner color difference meter and the haze measurements, using a Hazemeter attachment on the Gardner colorimeter. Test pieces were 3 X 3 X % inch sheets having glossy surfaces obtained by molding on chrome plates. All measurements were made at 23°C. 

Hard-sphere suspensions Haze measurements Haze... 

Table VIII. Transmission and Haze Measurements (unvulcanized glass laminates-...

They are sold under the tradenames of Lucite by E.I. duPont and Plexiglass by Rohm and Haas. Because of their chemical structure, acrylic resins are inherently resistant to discoloration and loss of light transmission. Parts molded from acrylic powders in their pure state may be clear and nearly optically perfect. The total light transmission is as high as 92%, and haze measurements average only 1%. 

Haze Measured on a hazemeter, haze is the scattering of light as it passes through a transparent material, resulting in poor visibility and/or glare. 

Fig. 2.9 Comparison of the increase in absorbance at 330 nm and haze measured as the average offset in the absorbance spectrum at 580-600 nm for PET films weathered in Rorida at 5° tilt and in the laboratory according to ASTM G154 Cycle 1 (UVA-340) at high irraditmce. The horizontal axes were scaled relative to each other to give the best overlay for change in absorbance at 330 nm...

Haze After exposure of each sample to outdoor weathering, haze measurements are to be conducted as per ASTM D1003-61 standard. For plastics used in lamp lenses, haze should not be greater than 30%, while for reflex reflectors or lenses used in front of reflectors, it should not be greater than 7%. In addition, plastics used for headlights (excluding cornering lamps) should also not show any deterioration. 

The transmission haze is the ratio of the diffuse transmittance (DT) to the total transmittance (TT). Haze measurement documentary standards recommend using an integration sphere to get the summation of transmission light directly, that is, the summation of DT and TT. Since the transmittance depends strongly on the geometry of the incident beam, every documentary standard has a strict definition for the incident beam, such as shape, size, divergent angle, and so on [15]. 

Currently haze measurement is carried out according to the methods described in several documentary standards such as ASTM D1003 and ISO 13468 among others. In each documentary the apparatus and the measurement precision are different [15]. 

Ideally, a minimum of three determinations should be made on separate specimens cut from the same sample and the average value reported. As the total haze of a specimen is highly dependent upon its surface characteristics, it is important that the surfaces of each specimen be free of blemishes, abrasion damage, and contamination. The precision of haze measurements is typically 0.1%, which is beyond the resolution of the human eye. 

The contribution of surface haze to the total haze of a specimen can be removed if its surfaces are coated with a liquid (such as immersion oil) with a refractive index approximately matching that of polyethylene ( == 1.5). Haze determined on coated specimens is indicative of the internal scattering. The surface haze value can be obtained by subtracting the internal haze from the total haze measurement. 

All color and haze measurements were performed on a GretagMacbeth Color i5 using a transmission adapter with a large area view and D65 illuminant. Color and haze were measured on the middle step (1.52 mm thickness) of the three-step chip. 

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