Optical properties of poly(2,6-dimethyl-1,4-phenylene oxide) film and its potential for a long-term solar ultraviolet dosimeter

Abstract

The optical properties of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) film have been characterised in order to develop an alternative method for UV dosimetry with a focus on long-term human exposure measurements. The dynamic range of PPO film was found to extend to 2 MJm -2 of broadband UV exposure independently of film thickness, providing an exposure range of roughly four summer days at subtropical latitudes. The sensitivity of the film to UV exposure was positively related to film thickness in the 20 to 40 μm range. Films of 40 μm thickness proved to be the most suitable for long-term human UV exposure measurements.The temperature independence of the response of 40 μm PPO film was established from 1.5°C to 50°C within a dosimeter response uncertainty of 6.5%. Dose-rate independence was also demonstrated within 8% of the mean dosimeter response. The spectral response approximates the CIE erythemal action spectrum between 300 and 340 nm, with a peak response at 305 nm. A large deviation from this action spectrum was observed at shorter wavelengths. Investigation of the angular response in both the azimuth and altitude planes showed a cosine error of less than 6.2% between 0° and 40°, and did not exceed 13.3% at any angle greater than 40°. These results indicate that PPO film satisfies the requirements for use as a UV dosimeter, and may be employed in long-term human exposure measurements.

Long-term UV dosimeter based on polyvinyl chloride for plant damage effective UV exposure measurements

“…This is due to differences in the amount of time the PVC dosimeter is 274 shaded compared to the period of time of shading of the PPO dosimeters. The average 275 difference of 11% and the maximum difference of 14% are within the estimated errors for PPO 276 dosimeters which have been estimated to be of the order of 15% (Lester et al, 2003). 277…”

“…Previously reported 105 PPO dosimeters (Lester et al 2003; Wainwright et al, 2013) were employed to evaluate the 106 exposures recorded by these PVC long-term dosimeters as it is not possible to measure with 107 radiometers the concurrent plant damage and UVB exposures to a number of leaves 108 simultaneously over a period of a month due to both the size of the radiometers and the need 109 to have multiple instruments for simultaneous measurements on a number of leaves. As PPO 110 dosimeters saturate after four to six days, they were used as sets of a series of dosimeters that 111 were replaced every four to six days and the cumulative UVB and UVBEplant exposures 112 evaluated over the long term exposure period.…”

Dosimeter based on 8-methoxypsoralen for UVA exposures over extended periods

“…The following tests have been undertaken in order to assess the capability of 8-MOP for use as a long term UVA dosimeter: the dark reaction, repeatability of measurement, seasonal dose response, cosine response, spectral response, temperature independence and dose rate independence [14,21,22].…”

“…This variance is in line with the reproducibility of other dosimeters. PPO has a variance of up to 6.5% dependent on exposure levels [22] and PVC has a variance of 5% [26].…”

Field calibrations of a long-term UV dosimeter for aquatic UVB exposures

“…[ 16], the response of the PPO dosimeter is not influenced in any way by fluctuations in local temperature. Therefore, changes in temperature over the different calibration sessions would not have had any effect upon the measured ΔA 320 data.…”