Luminescence glasses

Zinc compounds are generally colorless unless the other component, eg, chromate, is colored. The lack of color of most zinc compounds in visible light is a great advantage in that they do not color paint films, plastics, mbber, cosmetics, etc. However, when excited by various types of radiation and at various temperatures, zinc oxide, sulfide, selenide [1315-09-9], and related compounds exhibit luminescence, ie, they emit colored light (see Luminescent materials). Zinc-based phosphors can be produced in many colors, depending upon the added dopants. They are used in television tubes, luminescent glasses, and various specialty products. 

Epstein, M. S. Velapoldl, R. A. Blackburn, D. Evaluation of Luminescent Glass Spheres as Calibration Standards for Micro-spectrofluorimetry National Bureau of Standards Gaithersburg, MD Annual Task Report to Food and Drug Administration, 1984, 1985, 1986 also, paper to be submitted. 

Preparation of a polymer film with PtOEP PtOEP immobilized in a polymer film was formed by casting a mixture (0.1 mL) of 10 wt.% polymer film and PtOEP in toluene onto non-luminescent glass slides 1.4 x 5.0 cm in size. The PtOEP concentration in the film was 2.9 x lO moldm . The films were dried at room temperature and stored in the dark prior to use. The thickness of each film was determined by using a micron-sensitive calliper. The thicknesses of the prepared films were 50-80 pm. For ZnTPP, ZnTFPP and Ceo immobilized in PS film, the films are prepared by the same method. 

Although the luminescence intensity is dependent of the particular luminescent dye applied, the most important component of this sensor is the pH indicator. The C02-sensing properties of a film composed of a combination of a-naphtholphthalein with tetraphenylporphyrin (TPP) as the pH indicator and internal reference dyes may be used as an example." The exact constitution of this sensing film is a-naphtholphthalein/tetraoctyl ammonium hydroxide/cellulose/ tributyl phosphate/non-luminescent glass slide/TPP/polystyrene. 

Examples include luminescence from anthracene crystals subjected to alternating electric current (159), luminescence from electron recombination with the carbazole free radical produced by photolysis of potassium carba2ole in a fro2en glass matrix (160), reactions of free radicals with solvated electrons (155), and reduction of mtheiiium(III)tris(bipyridyl) with the hydrated electron (161). Other examples include the oxidation of aromatic radical anions with such oxidants as chlorine or ben2oyl peroxide (162,163), and the reduction of 9,10-dichloro-9,10-diphenyl-9,10-dihydroanthracene with the 9,10-diphenylanthracene radical anion (162,164). Many other examples of electron-transfer chemiluminescence have been reported (156,165). 

The cadmium chalcogenide semiconductors (qv) have found numerous appHcations ranging from rectifiers to photoconductive detectors in smoke alarms. Many Cd compounds, eg, sulfide, tungstate, selenide, teUuride, and oxide, are used as phosphors in luminescent screens and scintiUation counters. Glass colored with cadmium sulfoselenides is used as a color filter in spectroscopy and has recently attracted attention as a third-order, nonlinear optical switching material (see Nonlinear optical materials). DiaLkylcadmium compounds are polymerization catalysts for production of poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVA), and poly(methyl methacrylate) (PMMA). Mixed with TiCl, they catalyze the polymerization of ethylene and propylene. 

CdS colorants find use in plastics, paints, soaps, mbber, paper, glass, printing inks, ceramic gla2es, textiles, and fireworks. Luminescent pigments based on CdS—ZnS are also produced. Pigments based on CdS sell for 35—60/kg. The redder materials are more expensive. 

Shock Luminescence. Some transparent materials give off copious amounts of light when shocked to a high pressure, and thus they can serve as shock arrival-time indicators. A technique used by McQueen and Fritz (1982) to measure arrival times of release waves is based on the reduction of shock-induced luminescence as the shock pressure is relieved. Bromoform, fused quartz, and a high-density glass have been used for their shock luminescence properties. 

Cathodoluminescence (CL), i.e., the emission of light as the result of electron-beam bombardment, was first reported in the middle of the nineteenth century in experiments in evacuated glass tubes. The tubes were found to emit light when an electron beam (cathode ray) struck the glass, and subsequendy this phenomenon led to the discovery of the electron. Currendy, cathodoluminescence is widely used in cathode-ray tube-based (CRT) instruments (e.g., oscilloscopes, television and computer terminals) and in electron microscope fluorescent screens. With the developments of electron microscopy techniques (see the articles on SEM, STEM and TEM) in the last several decades, CL microscopy and spectroscopy have emerged as powerfirl tools for the microcharacterization of the electronic propenies of luminescent materials, attaining spatial resolutions on the order of 1 pm and less. Major applications of CL analysis techniques include ... 

Cormier, M. J. (1961). Biochemistry of Renilla reniformis luminescence. In McElroy, W. D., and Glass, B. (eds.), Light and Life, pp. 274-293. Johns Hopkins Press, Baltimore. 

Reisfeld R, Jorgensen CK (1991) Optical Properties of Colorants or Luminescent Species in Sol-Gel Glasses. 77 207-256... 

Substrates other than free cells were also examined for luminescence activity in the presence of tin and flavonol. For example, glass slides covered with a well-developed but uncharacterized biofllm growth were exposed to 4.5 x 10 H n-butyltin trichloride in ethanol for 60 min. The slides were subsequently rinsed with ethanol and exposed to 1.4 x H... 

Table II. Luminescence Wavelength Standards--Organics In Solution and Inorganic Ions In Glass Matrices...

Table VI. Characteristics of Luminescence from Inorganic Ion-Doped Glasses...

Figure 5. Two- and three-dimensional representations of relative luminescence flux of uranyl ion-doped glass beads, measured in a 100 X 100 raster with 10,000 data points. Depicted are a homogeneously doped bead (a) and a nonhomogeneously doped bead (b).

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