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Effects of a distribution of volume relaxation times in the annealing of bsc glass

1967; The National Institute of Standards and Technology; Volume: 71A; Issue: 3 Linguagem: Inglês

10.6028/jres.071a.031

2376-5704

Pedro B. Macedo, Albert Napolitano,

Theoretical and Computational Physics

Th e inAu e nce of a di s tributi on of relaxati on tim es is studi ed in ann e alin g ex pe rim e nts.A twore la xation tim e mode l is propose d , whi c h pe rmits th e c a lc ulatio n of th e di stributi on o f relaxation tim es from th e c ro sso ver data of Spinn e r and Napolitano as we ll as that of Ritland.Thi s mod e l al so chara cte ri zes th e stru c ture of any glass in te rm s of two parame te rs .Thu s , qu e nc hed e quilibrium as well a s no ne quilibrium glass we re compare d with rat e cooled gla sses with res pect to th e ir behavior upon furth e r ann ealin g a s well as the ir condu ctivit y at low te mpe ratures with excell e nt agree me nt.Boros ili ca te c rown gla ss was fo und to hav e a narrow di s tribution of re laxation time s which is parti c ular to assoc iated li quid monom e rs rath e r than pol yme rs.The res ult s c an be explained in te rm s of a topological mod el for th e di s tribution of re laxation tim es.Th e te mpe rature d e pe nden c e of th e vi scos it y is du e to a tru e ac tivation e ne rgy rath e r than a free volum e e ffec t.