The conformational energies for the various rotational isomers of model compounds for poly(oxytrimethylene), POM, , and poly(oxytetramethylene), P O W , were calculated by means of the empirical force field method, and statistical mechanics calculations were made for the configuration-dependent properties of POM3 and PO&. Although the dipole moment ratios of these polymers directly calculated from the results of the force field calculations agreed well with the observed ones, the estimated characteristic ratios did not agree with the observed ones. When the two geometric parameters of P O W were changed, excellent agreement between the experimental values and the estimated ones was obtained. In case of POM,, when only geometric parameters were changed, the agreement was less satisfactory. The value for the interaction energy E,, which is directly derived from the result of the force field calculation for the model compound of POM,, seems to be overestimated because of a fault minimum. The value for the interaction energy E, is estimated to be the same as for POM,. Moreover, when the four geometric parameters were changed, the estimated values agreed well with the experimental ones. The direct use of the results of the force field calculations is not always satisfactory, but the parameters obtained are a good initial set of parameters to reproduce the observed configuration-dependent properties.' )

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Conformational energies of various oligo(oxyethy1ene) isomers were calculated by the empirical force field method, and statistical mechanics calculations of the chain dimensions and the dipole moments were carried out. The results are seriously different from those obtained for poly(oxymethy1ene). Although the first-order steric interactions in POE are of the same order of magnitude as those in n-alkane chains, the second-order interactions are significantly different. The second-order interactions arising from rotations around two consecutive bonds of OCH,CH,OCH, in g* gT conformation have greatly reduced steric repulsions. It was found that the reduced second-order interaction plays an important role in the configurationdependent properties of POE. The agreement of the calculated values for the unperturbed dimensions and the temperature coefficients obtained from the force field method with experimentally observed ones is fairly good. a) Revised manuscript of 6. 12. 1982.

Wesynthesizedsilvermethacrylate,addedittoresinfordentaluse,andobservedcolorchangesintheresinfromcolorlessto red-purplefollowinglightirradiation.Therefore,0.01-0.10wt%silvermethacrylatewasaddedtotwotypesofresinpowder, i.e., self-curing resin produced by the polymerization of a barbituric acid derivative, quaternary ammonium, and an organometalliccompound(TypeI),andBPO-tertiaryamineresin(TypeII),andsampleswereproducedbypolymerization withtheattachedmonomer.Changeswithtimeinthecolorofsamplesfrom3hours(newsamples)to16days(oldsamples) afterpolymerizationandalsocolorchangesofoldandnewsamplesafterheatingwereevaluated.Subsequently,changesin colorwithvariationsinthelightintensity,irradiationtime,andwavelengthwereevaluatedintermsofcolordifferences.

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