Accession Number : ADA267621


Title :   Nonlinear Transmittance through Laser Protection Barrier: Reverse Photosaturation of 1-Phenylazo 2-Napthalenol in Polymer Host


Descriptive Note : Final rept.


Corporate Author : ARMSTRONG LAB BROOKS AFB TX


Personal Author(s) : Mayo, Michael W ; Roach, William P ; Bramlette, Craig M ; Gavornik, Michael D


Report Date : Jan 1993


Pagination or Media Count : 13


Abstract : We have measured the time-dependent transmittance of orange plastic samples composed of the dye 1 -Phenylazo 2-Napthalenol embedded in both polymethyl methacrylate (PMMA) and polycarbonate at various dye concentrations. The spectrophotometric transmittance below 520 nm is measured to be less than O. Ol% for the PMMA samples. However,a 6.4 mm thick PMMA sample containing 0.008% dye concentration reached a steady-state transmittance of 0.5% in 15 seconds for samples irradiated with continuous wave 514.5 nm light at 12 mW/sq cm. The transmittance reached a steady-state of 11% in 2.5 seconds when irradiated with 514.5 nm at greater than 600 W/sq cm incident. This represents a three order of magnitude increase in the transmittance at relatively low irradiance levels. In contrast, a 6.4 mm thick PMMA sample containing a dye concentration of 0.03% continued to transmit less than 0.0 1% with increased irradiance until the material reached damage threshold. We report ground-state absorption curves and transmittance versus time measurements for dye concentrations ranging from 0. 008% to 0. 15% in PMMA and polycarbonate. We compare the steady-state transmittance at 514.5 nm to the incident irradiance. We propose possible mechanisms associated with the nonlinear transmittance characteristics of 1- Phenylazo 2-Napthalenol.


Descriptors :   *STEADY STATE , *POLYMETHYL METHACRYLATE , *TRANSMITTANCE , *LASERS , *BARRIERS , *PLASTICS , *PROTECTION , *NONLINEAR SYSTEMS , REPRINTS , MEASUREMENT , CONTRAST , SPECTROPHOTOMETRY , POLYCARBONATES , PHENYL RADICALS , IRRADIATION , ABSORPTION , DYES , GROUND STATE , METHACRYLATES , DAMAGE , TIME , PHOTOCHEMICAL REACTIONS , MATERIALS , POLYMERS , CONTINUOUS WAVES , LIGHT


Subject Categories : Organic Chemistry
      Radiation and Nuclear Chemistry
      Polymer Chemistry
      Lasers and Masers


Distribution Statement : APPROVED FOR PUBLIC RELEASE