Photochemistry in polymer solids. 3. Kinetics for nonexponential decay of benzophenone phosphorescence in acrylic and methacrylic polymers

Horie, Kazuyuki; Morishita, Keiko; Mita, Itaru

doi:10.1021/ma00139a020

Cited by 81 publications

(75 citation statements)

References 11 publications

(15 reference statements)

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“…The activation energy for the carbonyl loss of PS-MIPK is calculated from the data in ref. 12 to be 5.5 kJ/mol between 64 and 104"C, and that for the benzophenone diffusion is reported to be 40 kJ/mol (19). The former is comparable to, but the latter is much larger than, that for benzoyl group removal in the case of PMMA-PIPK.…”

Section: -1 Temperature Dependence Of Benzoyl Group Removalmentioning

confidence: 90%

“…The activation energies below Tg for PMMA-PIPKs 06a and 35 were found to be 3.9 and 9.0 kJ/mol, respectively, which are a little smaller than the value of 12. ture dependence of quantum yield on T, and other secondary transitions was not found in Norrish type I cleavage of PE-MIPK and PS-MIPK, where smaller CO, CH;, and CH,CO' escape with great efficiency through polymeric glassy matrices (12). The dependence was observed in quenching of excited benzophenone in solid PMMA matrix, in which the quenching rate of phosphorescence was controlled by diffusion of benzophenone molecules (19). The activation energy for the carbonyl loss of PS-MIPK is calculated from the data in ref.…”

Section: -1 Temperature Dependence Of Benzoyl Group Removalmentioning

confidence: 92%

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Photodegradation mechanism of phenyl isopropenyl ketone – methyl methacrylate copolymers in the solid phase and their performance as a deep UV resist

Sugita¹,

Ishida²,

Kushida³

et al. 1995

Can. J. Chem.

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Phenyl isopropenyl ketone (PIPK) copolymer films were irradiated with a low-pressure mercury lamp, and benzoyl side-chain cleavage and main-chain scission at various temperatures were followed by UV spectral changes and gel permeation chromatography, respectively. Quantum yields of both reactions and the ratio of the latter to the former reaction increased markedly above their glass transition temperatures. The rnainchain scission continued to proceed by irradiation even after the side chain ceased to split. These experimental results suggest a new reaction mechanism of photosplitting of the methyl methacrylate ester side chain on the carbon adjacent to the C=C bond followed by p-scission, in addition to the known benzoyl side-chain cleavage followed by p-scission or C=C bond formation. The enhanced quantum yield for the main-chain scission of the PIPK copolymer at 130°C realized sensitivity of 100 mJ/crn2 as a DUV resist, which was 1200 times as high as that of poly(methy1 methacrylate) exposed at room temperature and developed under similar conditions. Key words: N o~~i s h type I cleavage, p-scission of main chain, temperature dependence, photosplitting of ester side chain, conjugated polymer radical.RCsumC : On a irradie des films de copolymtre de phCnyl(isopropCny1)cCtone (PIPK) A l'aide d'une larnpe au mercure A basse pression et on a observe le clivage de la chaine laterale benzoyle ainsi que la scission de la chaine principale, A diverses temperatures, en faisant appel respectivement aux changernents des spectres UV et A la chromatographie par permiation de gel. Les rendements quantiques des deux reactions ainsi que les rapports de la derniere reaction par rapport A la prernikre augmentent d'une faqon marquee au-dessus de leur temperature de transition vitreuse. Sous l'influence de l'irradiation, la scission de la chaine principale se produit encore m&me lorsque la chaine laterale a cesse de se cliver. Ces resultats exptrimentaux suggerent que, en plus du mecanisme connu irnpliquant un clivage de lachainelaterale benzoyle, suivi d'une scission-p ou de la formation d'une liaison C=C, il existe un nouveau mecanisme reactionnel pour la reaction de photoclivage de la chaine laterale du rnethacrylate de rnkthyle; il implique le carbone adjacent de la liaison C% et il est suivi par une scission-p. Le rendement quantique plus Clevt pour la scission de la chaine principale du copolyrnere PIPK, B 130°C, a permis d'atteindre une sensibilite de 100 rnJ/cm2 cornme resistante DUV; cette valeur est 1200 fois plus tlevte que celle du poly(rnCthacry1ate de rnethyle) expose i la ternpirature arnbiante et dCveloppC dans des conditions sernblables.Mots c l b : clivage Nonish de type I, scission-p de la chaine principale, relation avec la temperature, photoclivage de la chaine lattrale ester, radical polyrnere conjuge.[Traduit par la redaction]

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Section: -1 Temperature Dependence Of Benzoyl Group Removalmentioning

confidence: 90%

Section: -1 Temperature Dependence Of Benzoyl Group Removalmentioning

confidence: 92%

Photodegradation mechanism of phenyl isopropenyl ketone – methyl methacrylate copolymers in the solid phase and their performance as a deep UV resist

Sugita¹,

Ishida²,

Kushida³

et al. 1995

Can. J. Chem.

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“…The deviation was attributed to the diffusioncontrolled dynamic quenching (endothermic energy transfer) of the benzophenone triplet by side chain ester groups in these polymers. 3 The intensity independence of the non-single-exponential decay profile ofbenzophenone phosphorescence in PMMA was ascertained, 4 indicating the absence of biphotonic triplettriplet annihilation processes under the present experimental conditions. The decay study of benzophenone phosphorescence has been extended to cases in polystyrene and bisphenol A polycarbonate in the present paper.…”

mentioning

confidence: 64%

Photochemistry in Polymer Solids V. Decay of Benzophenone Phosphorescence in Polystyrene and in Polycarbonate

Horie

Tsukamoto

Morishita

et al. 1985

Polym J

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ABSTRACT:Decay curves and lifetimes of benzophenone phosphorescence in polystyrene and in bisphenol A polycarbonate (BPA-PC) at 80----433 K significantly reflect change in the molecular motion of matrix polymers such as glass transition, /3-transition, and }'-transition. The non-singleexponential decay. curves were observed in both polymers at temperatures between T, and T., and analyzed using the diffusion-controlled rate coefficient with a time dependent transient term for the dynamic quenching process of benzophenone triplet by phenyl or phenylene groups in the matrix polymers. The diffusion coefficients, D, of the reacting functional groups in polystyrene and BPA-PC for the wide temperature range below T. are much larger than that in PMMA in the same temperature range, showing a higher quenching ability of these polymers for the benzophenone triplet.

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“…This is similar to phosphorescence decay of benzophenone in polymers. 12 Since the size of free volume differs not only with the kind of polymer but specific structure as well as thermal history involving the physical processing and annealing, we also investigated the photochromism of Sa(H,2-Cl) in low density polyethylene, and poly(butyl methacrylate) films prepared by the melting or solvent-casting method. However, color development was observed only at low temperature (approximately -50°C).…”

Section: Effect Of Free Volume Of Polymer On the Photochromism Of Sa(mentioning

confidence: 99%

Photochromism of 2-Chloro-N-salicylideneaniline in Amorphous Polymer Solids

Yin

Haramoto

Nanasawa

1995

Polym J

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ABSTRACT:Photochromism of 2-chloro-N-salicylideneaniline, Sa(H,2-Cl), molecularly dispersed in amorphous polymer matrices was investigated under conventional steady-state irradiation. The final conversion of photochromic reaction in amorphous polymers was found to decrease with temperature due to notable influence on a thermal back reaction. The effect of polymer matrix on the thermal decay reaction was explained by the half-life (l/t, 12 ) of the colored species and concept of free volume of polymer matrices: the values at 20°C for Sa(H,2-Cl) in poly(methyl methacrylate) (PMMA), polystyrene (PS), and polycarbonate (PC) were I I.I, 3.0, and 2.5 min, respectively. This indicates that the size of free volume of PMMA is the smallest in the three polymers at room temperature. Arrhenius plots of l/t 112 for PC and PS broke obviously at 20 and 14°C in contrast to a linear relationship for PMMA, and apparent activation energies for the thermal decay reactions in both polymers were approximately half above the break points.KEY WORDS 2-Chloro-N-salicylideneaniline / Photochromism / Thermal Decay Reaction/ Half-Life of the Colored Species/ Photochromic Probe/ Free Volume/ Photochromism in polymer matrices has aroused much interest in connection with applications to EDRA W (erasable and directly reading and writing) memories, 1 and it has also been regarded as a molecular probe method for obtaining information of molecular motion of polymers in glassy state. 2 Reactions in amorphous polymer solids are generally governed by mobility and heterogeneity of reaction sites, so that photochromic processes may be retarded by polymer matrices compared with the liquid phase, and processes in amorphous polymers often deviate from first-order kinetics even if apparently elementary first-order reactions. 3 Salicylideneaniline and its derivatives (anils) are well-known organic photochromic compounds and their photochromism has been investigated in pure crystalline states and various matrices. 4 -6 In general, the photochrom-136 ism of anils in liquid solutions does not appear under conventional steady-state irradiation, because the photo-reaction yield of anils is relatively low and thermal reversion is extremely fast compared with other photochromic compounds. Therefore, the viscosity effect of solutions as well as other matrix effects on photochromism have been measured by laser-flash photolysis. 5 • 7 In this paper, the photochromism of 2-chloro-N-salicylideneaniline which is molecularly dispersed in amorphous polymer matrices was investigated under conventional steadystate irradiation at room temperature, and the matrix effects of polymer on the photochromism are discussed by comparing the thermal decay reactions in poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC), and others. The effect of polymer matrices on the thermal decay reactions was elu-

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Photochemistry in polymer solids. 3. Kinetics for nonexponential decay of benzophenone phosphorescence in acrylic and methacrylic polymers

Cited by 81 publications

References 11 publications

Photodegradation mechanism of phenyl isopropenyl ketone – methyl methacrylate copolymers in the solid phase and their performance as a deep UV resist

Photodegradation mechanism of phenyl isopropenyl ketone – methyl methacrylate copolymers in the solid phase and their performance as a deep UV resist

Photochemistry in Polymer Solids V. Decay of Benzophenone Phosphorescence in Polystyrene and in Polycarbonate

Photochromism of 2-Chloro-N-salicylideneaniline in Amorphous Polymer Solids

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