Terphenyl, ortho

Adam-Gibbs Model for the Supercooled Dynamics in the Ortho-Terphenyl Ortho-Phenylphenol Mixture. 

The same t3q)e of thermal history caused solid-like behavior in the supercooled molecular liquid ortho-terphenyl [35], a fragile molecular glass-former, as well as in glycerol, a stronger, hydrogen-bonded one. 

Earlier dielectric studies under elevated pressure [20,105-110] had found temperature-pressure superpositioning at constant xa in a few molecular glass-formers including ortho-terphenyl (OTP), di(2-ethylhexyl) phthalate, tricresyl phosphate, polyphenyl ether, and refined naphthenic mineral oil, although the temperature and pressure ranges are not as wide as achieved in more recent measurements. 

The available studies of molecular glass-formers are wider, for both materials and techniques. For ortho-terphenyl (OTP), the Kohlrausch parameters for the a-relaxation by PCS at different temperatures and pressures [121,122] have been reported. The stretching parameters versus a-relaxation time xa for... 

Cicerone, M. T., and Ediger, M. D., Relaxation of spatially heterogeneous dynamic domains in supercooled ortho-terphenyl. 7. Chem. Phys. 103, 5684 (1995). 

However, in order for this explanation to be consistent with the observed monotonic increases of the products A and Dttc as the temperature is lowered toward A the breadth of the relaxation time distribution has to increase (or the Kohlrausch exponent, l-n, has to decrease) correspondingly. However, for two glassformers, ortho-terphenyl (OTP) and tni naphthylbenzene (TNB) which show the breakdown of the SE and DSE relations, Richert and coworkerss recently reported that their dielectric spectra are characterized by a temperature independent width (e.g. l-rid is constant and is equal to 0.50) from 345-417 K in the case of TNB. The Tg of TNB is 342 K. Photon correlation spectroscopic and NMR measurements all indicate a temperature-independent distribution of relaxation times. Thus, the data of TNB and OTP contradicts the explanation based on spatial heterogeneities. On the other hand, an alternative explanation based on intermolecular coupling (originating from many-molecule relaxation) continues to hold. ... 

Bohmer and coworkers " used spin-lattice relaxation weighted stimulated-echo spectroscopy to find evidence for a correlation of the a- and the JG P-relaxation times above the calorimetric glass transition temperature of ortho-terphenyl, D-sorbitol, and cresolphthaleindimethylether (CDE or KDE). They found that the cr-relaxation can be modified by suppressing the contributions of some subensembles of the JG p-relaxation in these glassformers. An earlier deuteron NMR experiment also gave indication of a possible correlation of the a- and JG p-relaxations of polystyrene. ... 

Tolle, A. (2001) Neutron scattering studies of the model glass former ortho-terphenyl. Rep. Prog. Phys. 64, 1473... 

Naoki, M., Endou, H., and Matsirmoto, K. (1987) Pressure effects on dielectric-relaxation of supercooled ortho-terphenyl, J. Phys. Chem. 91,4169... 

This mechanism requires the formation of hydrogenated ortho-terphenyl derivatives such as VIII, which were not noted by gas-liquid chromatography or infrared. 

SYNONYMS diphenylbenzenes, mixed terphenyls, meta-terphenyl, ortho-terphenyl, para-terphenyl, phenyl biphenyls, terbenzenes, triphenyls. 

Synonyms/Trade Names o-Diphenylbenzene 1,2-Diphenylbenzene 2-Phenylbiphenyl 1,2-Terphenyl ortho-Terphenyl o-Triphenyl ... 

GLASS TRANSITION IN ORTHO-TERPHENYL GREET RJ TURNBULL D... 

Very recendy, Schmidt et al. synthesized novel polyamides 51 by using arylsubstituted terephthalic acids moieties such as para- or ortho-terphenyl-2,5-dicarboxylic adds in combination with sul tituted and non-coplanar diamines [70]. Those polyamides 51 from substituted diadds, diamines or non-coplanar diamines showed high solubility in DMAc, and in most cases without addition of inorganic salts (LiO). In DMAc (liQ), polyamide 51ca = 1.63 dl/g)... 

It will be evident that whilst polymers are able to form glasses they are not unique and that the basic characteristics of the glassy state are common to a number of organic and inorganic materials. Some materials, such as ortho-terphenyl, form a glass if cooled quickly and subsequently change to a crystalline form. ... 

Figure 7.1 Schematic of the variation in the volume with temperature of glassy and crystalline ortho-terphenyl (a) cooling-heating (b) variation with cooling rate.

Fig. 5. Boson peak energy as a function of monomer mass for amorphous polymers and as a function of molecular mass for organic molecular glasses. Amorphous polymers polyethylene (PE) [29], poly(vinyl alcohol) (PVA) [152], cis-1,4-polyhutadiene (PB), polyisobutylene (PIB), frans-1,4-polychloroprene (PCP), atactic polyst ene (PS), atactic poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate) (PET) [30, 34], atactic polypropylene (a-PP) [95],polyisoprene with deuteratedmethyl group (PIP-dj) [36],polycarbonate (PC) [91],polyimide (AURUM) [39]. Molecular glasses propylene (P), 1-butene (B), 3-methyl pentane (MP),ortho-terphenyl (OTP),ethylbenzene (EB) [38]...

TERPHENYLS Triphenyls, ortho>Terphenyl, meta Tcrphenyl, para-Ter-phenyl, Mixed ter-phcnyls. Diphenyl benzenes None hazardous 325 to 405(oc) >... 

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