WorldCat Identities

Windsor, M. W.

Works: 13 works in 14 publications in 1 language and 14 library holdings
Publication Timeline
Most widely held works by M. W Windsor
Research on triplet states and photochromism( Book )

2 editions published in 1964 in English and held by 2 WorldCat member libraries worldwide

Research studies are described on the photochromic properties of the triplet states of aromatic compounds and their application to the problem of eye-protection against nuclear weapons. A Cary spectrophotometer has been specially modified to allow the transmission of a sample to be measured while it is under irradiation by a repetitively tri.gered flash lamp. Using this apparatus, triplet-triplet absorption spectra have been recorded for several new compounds in plastic media. Coronene, naphthocoronene and naphthochrysene are all found to have strong T-T absorption extending over most of the visible region. (Author)
Triplet to triplet absorption in organic molecules for use in photochromic devices by J.L Kropp( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The photochromic properties of several substituted aromatics and heterocyclics have been investigated. The absorption spectra, phosphorescence lifetime T-T absorption spectra and the product of triplet extinction coefficient and triplet formation efficiency, were evaluated for representative compounds. Using these data the photochromic properties of heterocyclics are compared to their hydrocarbon analogs. The values of the maximum triplet formation efficiency are lower for heterocyclics than for aromatics. However, broader T-T absorption and more efficient absorption for pumping light suggest that, on balance, heterocyclics are comparable to aromatic hydrocarbons in their effectiveness as photochromic materials. The variation of solvent induces large changes in the photochromic properties of heterocyclics thus providing a useful additional parameter for adjusting their properties. These differences also promise to shed light on the mechanism of radiationless transitions in these compounds. Recommendations for further studies to improve the photochromic properties of heterocyclics are made. (Author)
Picosecond Studies of Primary Charge Separation in Bacterial Photosynthesis( Book )

1 edition published in 1980 in English and held by 1 WorldCat member library worldwide

Picosecond Flash Photolysis: Transient Absorption in Sn(IV), Pd(II), and Cu(II) Porphyrins( Book )

1 edition published in 1974 in English and held by 1 WorldCat member library worldwide

From picosecond flash photolysis and spectroscopy, the absorption spectra of the first excited singlet S(1) and of the first excited triplet T(1) of (OEP)SnCl2 (Octaethylporphinatotin dichloride) are determined. The triplet quantum yield is determined. Similar S(1) and T(1) phototransient absorption spectra occur in (OEP)Pd. However, two Cu porphyrins show only one phototransient absorption spectrum. T(1) absorption results are generally consistent with the available earlier spectroscopic studies made with other techniques. (Modified author abstract)
Radiative and radiationless processes in aromatic molecules: pyrene( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The fluorescence yield, triplet yield, and fluorescence lifetime for pyrene-h10 and pyrene-d10 have been measured as a function of temperature. The phosphorescence yield, and phosphorescence lifetime, have also been determined. However, in pyrene-d10 the fluorescence yield increases with increasing temperature, indicating that the rate constant for intersystem crossing has a temperature-dependent part. The variation of fluorescence lifetime and triplet yield with temperature for a pyrene-h10 is attributable in toto to a temperature-sensitive internal conversion; in pyrene-d10 both internal conversion and inter-system crossing are temperature-dependent and contribute to the observed variations. (Author)
Electron Transfer from Photoexcited Bacteriopheophytin to p-Benzoquinone in Cationic Micelles( Book )

1 edition published in 1980 in English and held by 1 WorldCat member library worldwide

Studies of radiationless transitions in coronene using nanosecond laser photolysis and spectroscopy( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The technique of nanosecond laser photolysis and spectroscopy was used to observe absorption from both the lowest excited singlet S1 and the lowest triplet T1, of coronene. The technique employs a Q-switched ruby laser to produce both a 30 nsec pulse at 347nm for excitation plus, at the same time, a laser-induced spark which provides a background continuum for absorption spectroscopy. New transient absorption bands were observed for coronene at 520 and 380 nm and attribute these to absorption by the S1 state. The new bands locate previously unobserved higher singlet levels of g parity. These bands decay over a period of several hundred nanoseconds and are concomitantly replaced by absorption bands characteristic of the lowest triplet state, thus providing a pictoral record of the process of intersystem crossing. The T-T absorption spectrum of coronene was also obtained in epoxy plastic out to 1.14 microns using a double-beam cross-irradiation technique. New maxima in the infra-red serve to locate the energies of three low-lying excited triplet levels. Coronene intersystem crossing from higher singlet to the triplet manifold may occur
Triplet materials research and eye-protective system( Book )

1 edition published in 1968 in English and held by 1 WorldCat member library worldwide

The second prototype model of a 6 x 8-inch photochromic, windshield segment has been developed, tested and delivered to the Air Force. The device is designed to protect Air Force Pilots against flash blindness resulting from viewing nuclear explosions. The reversible photochromic darkening is based upon the absorption of metastable triplet states of aromatic molecules. These compounds are incorporated into a transparent plate of epoxy plastic. Two plates are attached on the outside of a 6 x 8 x 1 1/2-inch quartz block and the triplet states are excited by uv light from two flash lamps. Black-glass filters absorb the visible light from the flash lamps which would otherwise dazzle the pilot. With a 3000J excitation flash the windshield segment darkens from an open-state absorbance of 0.08 to absorbances of 0.89, 1.68, 2.18 and 2.53, respectively, at times of 50, 100, 150 and 500 microseconds after the start of the flash. The open-state transmission, optical quality and rapidity of buildup of absorbance of the present device are greatly improved compared to the performance of the windshield segment developed on the preceding contract. The windshield segment reopens to half the closed-state absorbance in 1.6 seconds. (Author)
Picosecond Studies of Electronic Relaxation in Triphenylmethane Dyes by Fluorescence-Upconversion( Book )

1 edition published in 1980 in English and held by 1 WorldCat member library worldwide

Nanosecond and Picosecond Photochemistry with Lasers( Book )

1 edition published in 1972 in English and held by 1 WorldCat member library worldwide

Pulsed lasers are excellent light sources for studying primary events in photochemistry. Previously a Q-switched ruby laser and a laser-induced spark was used to observe excited singlet states of aromatic compounds on a nanosecond time scale. In the reported research the authors have extended the time resolution of laser photolysis onto the picosecond time range. They used the second harmonic (530 nm) of a mode-locked neodymium/glass laser as an excitation source. The self-phase modulation continuum produced when 530nm picosecond laser pulses are focussed into glass, water and other optical media was employed. Using the continuum as a monitoring source they observed inverse Raman spectra in several molecules and a short lived transient absorption in Rhodamine 6G. Observation of short lived absorption by excited molecular states is of importance in understanding the dynamics of laser control materials such as those used for Q-switching and mode-locking. (Author)
Picosecond Flash Photolysis and Spectroscopy: Bis-(4-Dimethylaminodithiobenzel)-Ni(II), (BDN)( Book )

1 edition published in 1974 in English and held by 1 WorldCat member library worldwide

The transient absorption spectrum of an electronically excited dithiene, bis-(4-dimethylaminodithiobenzil)-Ni(II), BDN, was measured with 10 ps temporal resolution and 1 nm wavelength resolution. For a series of 'heavy atom' solvents, both the ground state and the excited state spectra remained constant while the decay kinetics of the excited state absorption, as well as the recovery from ground state bleaching, varied. The excited state spectrum can plausibly be fit by a particular one electron transition between previously calculated molecular orbitals, although this clearly does not prove that these orbitals provide the best description for the excited states. The authors comment on three possibilities within the framework of the ground state virtual orbital picture. The recently developed techniques will be generally applicable in probing the photodynamics of presently intractable molecular species. The significance of the data for laser mode-locking is discussed. (Modified author abstract)
Photochromic eye-protective device based on triplet absorption( Book )

1 edition published in 1966 in English and held by 1 WorldCat member library worldwide

A prototype 6 x 8-inch photochromic windshield segment was developed and delivered to the Air Force. The device is designed to protect pilots against flash blindness caused by exposure to nuclear explosions. The reversible photochromic darkening is based upon absorption of visible light by metastable triplet states of aromatic molecules. The active compounds are incorporated into solid sheets of transparent plastic. Three sheets of plastic are arranged in an N-type configuration and the triplet states are produced by UV excitation from two flash lamps. Black glass filters prevent visible light from the flash lamps from dazzling the observer. With a 1900 joule input to the flash lamps, the triplet-state windshield segment attains within one millisecond an optical density, weighted for eye-response, that varies from 1.4 along a line midway between the flash lamps to 2.7 close to each flash lamp. The open-state transmittance is 65% and the device re-opens to one-half this transmittance in approximately 2 seconds. (Author)

1 edition published in 1963 in English and held by 0 WorldCat member libraries worldwide

Results highly suggestive of laser action have been obtained for benzophenone and a chelate of terbium in rigid organic glasses at 77 K.A resonant laser cavity employing multiple-layer, dielectric-coated, confocal mirrors was constructed. This was used for the low-temperature glass studies. Extension of observations to liquid systems is a simple matter using the above cavity. A high power flash apparatus of 12,800 joule capacity was constructed for excitation purposes. A technique was developed for flashing lamps immersed in liquid nitrogen. Techniques were developed for incorporating aromatic compounds and chelates into plastic rods for laser evaluation. Lifetimes of aromatic compounds in plastics were measured. Rareearth ions and chelates were evaluated for potential laser action in liquid solutions and experimental studies were started. Novel ways of experimentally increasing quantum yields are under consideration. (Author)
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English (14)