Fluorescence and absorption of polystyrene exposed to UV laser radiation

Nurmukhametov, R. N.; Volkova, L. V.; Kabanov, S. P.

doi:10.1007/s10812-006-0035-y

Cited by 36 publications

(38 citation statements)

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“…Nurmukhametov et al [42] have exposed PS films and solutions with UV laser light beam (λ = 248 nm) and observed changes in absorption and luminescent properties. They observed formation of optical centers with absorption band from 280 nm to 460 nm with fluorescence band from 330 nm to 520 nm.…”

Section: Methodsmentioning

confidence: 99%

Direct Writing in Polymers with Femtosecond Laser Pulses: Physics and Applications

Deepak¹,

Soma²,

Desai³

2012

Laser Pulses - Theory, Technology, and Applications

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Section: Methodsmentioning

confidence: 99%

Direct Writing in Polymers with Femtosecond Laser Pulses: Physics and Applications

Deepak¹,

Soma²,

Desai³

2012

Laser Pulses - Theory, Technology, and Applications

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“…To date, a rather large amount of data has been accumulated on the photochemistry and radiation chemistry of polystyrene [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…4, curves 1′-3′). We previously studied the changes in the fluorescence spectra of irradiated polystyrene in [11]. The results of [11] were explained by structural chemical conversions responsible for appearance of defects in the polymer chain in the form of polyconjugated fragments.…”

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confidence: 99%

“…We previously studied the changes in the fluorescence spectra of irradiated polystyrene in [11]. The results of [11] were explained by structural chemical conversions responsible for appearance of defects in the polymer chain in the form of polyconjugated fragments. For excitation of the irradiated polystyrene by light with λ = 310 nm, a fluorescence spectrum is obtained in which the most intense band is the one with maximum in the 355-365 nm region (Fig.…”

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confidence: 99%

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Fluorescence and absorption of a polystyrene-based scintillator exposed to UV laser radiation

et al. 2007

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We have established that exposure of polystyrene-based scintillator samples to UV laser radiation (248 nm) leads to a significant decrease in the fluorescence intensity. We have carried out a spectral analysis of the luminescent and absorption properties of the scintillator, which allowed us to determine the major factor in the decrease in luminescence intensity of the samples exposed to UV radiation. We propose a new hypothesis for the mechanism of the processes leading to the decrease in light output of the scintillator during operation. Introduction.A plastic scintillator is a composite consisting of an optically transparent plastic and added luminophores. A plastic scintillator displays bright luminescence when exposed to ionizing radiation and is rather stable relative to such exposure. Scintillators are made from such composites in the form of optical fibers, films, and plates with large surface area, and also bulk blocks of any size or shape, which significantly expands the possibilities for their application. The advantage of plastic scintillators is their fast response (the radioluminescence lifetime ranges from fractions of a nanosecond to several nanoseconds). They are used for radiation detection and dosimetry.The most widely used plastic scintillators are based on polystyrene with added luminophores: p-terphenyl (p-TP) and 1,4-bis(2-(5-phenyloxazolyl))benzene (POPOP). Polystyrene plastic is the most radiation resistant among the known synthetic polymers [1]; it has high transparency over a broad spectral range (λ > 290 nm). However, we should point out that the indicated characteristic is seen only in the very pure polymer. Commercial polystyrene contains impurities and structural defects absorbing in the 290-400 nm region [2][3][4].A general disadvantage of plastic scintillators is gradual loss of scintillation efficiency during operation. As the absorbed dose of ionizing radiation increases, the light output of the scintillator decreases. As the characteristic for radiation resistance, we take the value of the absorbed dose D 1/2 at which the light output is half of the initial value. For polystyrene scintillators, D 1/2 ≈ 600 kGy [3].The radiation-induced physicochemical changes leading to a decrease in the light output of a plastic scintillator have been the subject of many studies [3,[5][6][7][8][9][10]. Special attention has been focused on the loss of transparency in the plastic. It has been established that this is due to the appearance of "induced" absorption bands that are relatively intense in the 300-400 nm region and low-intensity in the visible region. The bands that appeared were assigned to macroradicals formed on exposure to radiation, some of which proved to be short-lived while others were rather stable. These data provided the basis for established ideas about the reasons for radiation-induced wear in plastic scintillators. We should point out that in some papers (see, for example, [9]), bands were seen which could not be attributed to radicals, and they were assigned to unident...

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“…On exposure to natural sunlight, PS has been found to undergo oxidative degradation through photo-induced excitation as a result of absorbing ultraviolet (UV) radiation (295-400 nm) [2]. In general, PS has an absorption maximum that is well below 280 nm, which is assigned as the s 0 to s 1 transition in a benzene ring [8]. However, absorption of longer wavelengths (>300 nm) is also thought to occur due to the presence of trace amounts of impurities, structural defects or charge transfer complexes [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%