We present our results on optical waveguides formed by thermal diffusion of ions in glass. It was found that the peak of the ion-exchanged region can be shifted into the substrate interior by limiting the diffusion process. We also found that low loss films (<0.1 dB/cm) can be fabricated using this process and that the modal losses in these films do not agree with those losses predicted by existing theories. Also, the ion-exchange process has proved to be a simple means for fabricating tapered-edge couplers.

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Certain complex, sulfur-containing sodalite-type silicates, synthesis of which is described, exhibit under 3650 -~ excitation an emission extending from 5000 .~ to beyond 7000 A, the spectrum varying with composition. The band structure of this emission at -196~ is similar to the emission structure shown by a mixture of Na2S~ and Na2SO4. It is concluded that luminescence is due to the presence of Na~S~, which replaces part of the NaC1 normally present in sodalite.Synthetic sodalites eontainizlg both NaC1 and Na,_,S are tenebreseent, coloring purple on irradiation with 2537 and 3650 ~. ultraviolet.

ELECTRIC MOMENTS OF CERTAIN ESTERS 365 ments and would be even higher were it not for molecular association.A study of the molecular structure of the esters has indicated that several possible structures may exist for each compound, but experimental data limits these possible structt~res to ones which contain a cis form. It is also concluded that the molecules exist for the most part in a nonplanar form. ABSTRACTThe thermoluminescence of manganese-activated calcium fluoride has been found to be dependent on both its manganese content and the presence of other foreign ions. Sodium and oxygen promote high temperature glow peaks, whereas the addition of trivalent cations causes the thermoluminescence of oxygen-containing material to occur at lower temperatures. Thermoluminescence may be excited by x-rays, by mechanical handling, or by irradiation with blue light. Glow peak positions are independent of the method of excitation.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.230.243.252

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