Kinetic peculiarities of rhodamine 6G photodegradation in polymethylmethacrylate

Journal Article · Wed Oct 01 04:00:00 EDT 1986 · J. Appl. Spectrosc. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00661047· OSTI ID:6948342

Mardaleishvili, I R; Anisimov, V M

Dye-activated polymer matrices have found recently wide technological applications as active laser media. The kinetic mechanism for dye photodegradation has been studied in this work for polymethylmethacrylate (PMMA) activated by rhodamine 6G (R6G). It has been found that the dye molecules are not equivalent with respect to their stability to the light and the effective width of their distribution over this parameter depends on the photon energy acting on the system. For the short wavelength UV irradiation (lambda = 254 nm) the distribution is narrow and it widens with an increase in the excitation wavelength. Optically transparent PMMA films (molecular weight 160,000 and thickness ca.20 mum) have been used in the present work. The necessity of accounting for the kinetics and effectiveness of the relaxation processes leading to a change in the reactivity of the molecules added to the polymer matrix limit the applicability of the kinetic stabilization method. A detailed study of the relaxation processes has been carried out, where it has been demonstrated for a number of polymer matrices, including PMMA, that a relaxation of guest molecules, leading to an enhancement of their reactivity, is effective only at the temperatures close to T /SUB c/ of the polymer. For PMMA activated by R6G the dark incubation of the previously irradiated sample for 30 min at 90 C leads to a substantial increase in the further photodegradation process. This is due to the fact that the relaxation process leads to an increased fraction of the highly reactive molecules. Diagrams are included.

• OSTI ID: 6948342
• Journal Information: J. Appl. Spectrosc. (Engl. Transl.); (United States), Journal Name: J. Appl. Spectrosc. (Engl. Transl.); (United States) Vol. 44:4; ISSN JASYA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ACTIVATION ENERGY
AMINES
CARBOXYLIC ACIDS
CHEMICAL ACTIVATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DECOMPOSITION
DYES
ELECTROMAGNETIC RADIATION
ENERGY
ESTERS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
LASER MATERIALS
MATERIALS
MATERIALS TESTING
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC POLYMERS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PMMA
POLYACRYLATES
POLYMERS
POLYVINYLS
RADIATIONS
REACTION KINETICS
REAGENTS
RELAXATION
RHODAMINES
STABILIZATION
TESTING
ULTRAVIOLET RADIATION