49:, where a special process is used to create a dealkalized inside surface that is more resistant to interactions with liquid products put inside the container. However, the term dealkalization may also be generally applied to any process where a glass surface forms a thin surface layer that is depleted of alkali ions relative to the bulk. A common example is the initial stages of glass corrosion or
237:
water to a freshly made bottle and rolling the bottle gently to pass the water completely over its inside surface. The pH of the rinse water is then measured; untreated containers will tend to yield a slightly alkaline pH in the 8-9 range due to extracted alkali, while dealkalized containers tend to yield a pH that remains approximately neutral.
129:
in any way against changes in pH. If alkali is leached from the glass into the product, the pH will begin to rise (i.e. become more alkaline), can eventually reach a pH high enough that the solution begins to attack the glass itself quite effectively. By this mechanism, initially neutral alcohol
240:
A much more thorough version of this test is outlined in various international and domestic testing standards for glass containers, all with comparable methodologies. These tests evaluate the hydrolytic stability of the containers under more severe conditions, wherein containers, filled close to
236:
Routine tests for surface dealkalization in the glass container industry all generally aim to evaluate the amount of alkali extracted from the glass when it is rinsed with or exposed to purified water. For example, dealkalization can be quickly checked by introducing a small volume of distilled
218:
mixed with air) into bottles at high temperatures. The gas can be delivered to the container either in the air used in the forming process (i.e. during the final blow of the container into its desired shape), or with a nozzle directing a stream of the gas down into the mouth of the bottle as it
257:
While not routine, dealkalization can also be measured in a variety of other ways. Since dealkalized surfaces are more chemically durable, they are also more resistant to weathering reactions, and appropriate evaluation of this parameter can give indirect evidence of a previously dealkalized
210:
salt or aqueous solutions thereof. These materials are introduced inside the container after forming and decompose into gases in the annealing lehr, where the resulting sulfur-containing gas mixture carries out the dealkalization reaction. This method is purportedly safer than flooding the
249:
with acid to evaluate the pH of the water, and therefore the equivalent amount of alkali extracted during the heat cycle. The alkali content of the rinse water can also be evaluated more directly by chemical analysis of the rinse water, as outlined in more recent versions of the
European
162:
Dealkalizing glass containers is accomplished by exposing the glass surface to reactive sulfur- or fluorine-containing compounds during the manufacturing process. A rapid ion-exchange reaction proceeds that depletes the inside surface of alkali, and is performed when the glass is at high
254:" containers, thus setting them apart from their untreated counterparts due to their improved resistance to product interactions (as opposed to "Type III", which is standard, untreated soda-lime glass, or "Type I", which is reserved for highly resistant borosilicate glass).
134:
or particles in the fluid. Dealkalization treatment hinders this process by removing alkali from the inside surface. Not only does this mean less extractable alkali in the glass surface directly contacting the product, but it also creates a barrier for the
101:
For glass containers, the goal of surface dealkalization is to render the inside surface of the container more resistant to interactions with liquid products later put inside it. Since the treatment is directed primarily at changing the properties of the
453:
Geotti-Bianchini, F., E. Guadagnino, et al. (1998). "Surface reactions of type II sulfur-treated glass containers during autoclave testing in water." Proceedings of
International Congress on Glass, 18th, San Francisco, CA, United States, July 5–10, 1998:
30:, wherein a thin surface layer is created that has a lower concentration of alkali ions than is present in the underlying, bulk glass. This change in surface composition commonly alters the observed properties of the surface, most notably enhancing
223:
that reacts with the glass surface and serves to dealkalize it. The resultant surface is virtually free from any residues of the process. This treatment is also known as the Ball I.T. process (I.T. standing for internal treatment) as
443:
Verita, M.; Geotti-Bianchini, F.; De Riu, L.; Pantano, C. G.; Paulson, T. E.; "Surface analysis of internally treated dealkalized containers" Fundamentals of Glass
Science and Technology, , Vaexjoe, Swed., June 9–12, 1997 (1997),
211:
annealing lehr since the unreacted components in the gas mixture will tend not to escape to the atmosphere, but rather react with each other and recreate the original salt in the container that can later be rinsed away.
45:
ions in their internal structure. Since sodium is an alkali element, its selective removal from the surface results in a dealkalized surface. A classic example of dealkalization is the treatment of
166:
Historically, sulfur-containing compounds were the first materials used to dealkalize glass containers. Dealkalization proceeds through the interdiffusion/ion-exchange of Na out of the glass and H/H
154:
of the solution, which not only inhibits eventual attack of the glass as previously described, but can also be important in maintaining the efficacy or stability of sensitive product formulations.
380:
Yashchishin, I. N. and T. B. Zheplinskii (1996). "Improving the chemical resistance of glass containers by thermochemical treatment with a reagent solution." Glass and
Ceramics 53(5): 135-137
150:, they are also at times dealkalized in order to minimize the possibility of alkali leaching from the glass into the product. This action helps to avoid undesired changes in pH or
319:
Although silicate glasses set the standard in terms of chemical resistance, they are generally susceptible to high-pH solutions. This is the same reason that bleach and other
64:
glasses, dealkalized surfaces are also often considered "silica-rich" since the selective removal of alkali ions can be thought to leave behind a surface composed primarily of
202:) gases—especially in the presence of water, which enhances the reaction. However, this practice fell into disfavor due to environmental and health concerns regarding SO
182:, on the glass surface that must be rinsed away prior to filling. On manufacturing lines, one way in which this process was done was by flooding the annealing
371:
Ryder, R. J., Poad,W. J., et al. (1982). "Improved internal treatments for glass containers." Journal of the
Canadian Ceramic Society (1932-1986) 51: 21-8.
336:
Bacon, F. R. and O. G. Burch (1940). "Resistance of glass bottles to neutral alcoholic solutions." Journal of the
American Ceramic Society 23(5): 147-151
323:
are not stored in glass containers. For more information on general corrosion of glass, see, for example,D. E. Clark, C. G. Pantano, and L. L. Hench,
219:
passes on a conveyor belt after forming but before annealing. The mixture gently combusts inside the bottle, creating an extremely small dose of
1031:
930:
72:). To be precise, dealkalization does not generally involve the outright removal of alkali from the glass, but rather its replacement with
170:
O into the glass, along with the subsequent reaction of the sulfate species with available sodium at the surface to form sodium sulfate (Na
250:
Pharmacopoeia. According to the
Pharmacopoeia standards, internally treated or dealkalized soda-lime glass containers are designated as "
482:
214:
Treatment with fluorine-containing compounds is typically accomplished through the injection of a fluorinated gas mixture (e.g.
258:
surface. It is also possible to evaluate dealkalization through the use of advanced, surface analytical techniques such as
390:
263:
955:
751:
259:
130:
products can achieve a pH where the glass container itself begins to slowly dissolve, leaving thin, siliceous
867:
844:
700:
475:
54:
771:
146:
that are intended to hold medicinal products. While many of these items are composed of more durable
731:
652:
542:
1036:
1000:
632:
285:
60:
A dealkalized surface may have either no alkali remaining or may just have less than the bulk. In
995:
862:
736:
228:
held the patent and developed the first commercially available system implementing this process.
468:
425:
United States
Pharmacopoeia, Section 661, "Containers; Chemical Resistance – Glass Containers"
415:
ASTM C225-85(2004) Standard Test
Methods for Resistance of Glass Containers to Chemical Attack
804:
612:
960:
834:
746:
582:
572:
414:
57:
from the surface region by interactions with water, forming a dealkalized surface layer.
872:
8:
1046:
980:
907:
902:
824:
799:
766:
627:
50:
275:
1041:
887:
809:
557:
547:
215:
183:
147:
106:
surface in contact with the product, it is also referred to as "internal treatment".
965:
935:
892:
829:
814:
726:
617:
220:
756:
741:
511:
320:
225:
207:
109:
The most common example of its use with containers is on bottles intended to hold
950:
945:
794:
690:
667:
662:
647:
642:
637:
597:
567:
295:
290:
195:
126:
110:
46:
38:
912:
882:
434:
European
Pharmacopoeia, Chapter 3.2.1 "Glass Containers for Pharmaceutical Use"
394:
187:
151:
1025:
819:
776:
682:
657:
552:
300:
622:
245:
at 121 °C for 1 hour. After cooling to room temperature, the water is
985:
940:
897:
587:
562:
516:
131:
85:
1010:
975:
695:
577:
206:-type gases. An alternative method for sulfate treatment is with solid
178:). The latter is left behind as water-soluble crystalline deposits, or
1005:
970:
839:
607:
602:
460:
163:
temperature, usually on the order of 500–650 °C or greater.
246:
242:
241:
capacity with purified water, are covered and then heat-cycled in an
136:
77:
31:
990:
761:
537:
532:
61:
710:
786:
592:
266:, which give direct measurements of glass surface composition.
73:
65:
42:
24:
113:. The reason for this is that some alcoholic spirits such as
37:
Many commercial glass products such as containers are made of
705:
672:
506:
491:
280:
142:
The same logic applies in pharmaceutical glass items such as
139:
of alkali from the underlying bulk glass into the product.
114:
20:
143:
27:
118:
122:
391:"Consol glass statement on fluorinated gas treatment"
345:
F. R. Bacon, "Chemical Durability of Silicate Glass"
19:is a process of surface modification applicable to
41:, and therefore have a substantial percentage of
1023:
91:
931:Conservation and restoration of glass objects
476:
358:D. E. Clark, C. G. Pantano, and L. L. Hench,
231:
84:O) in the structure through the process of
483:
469:
362:(Books for Industry, New York, N.Y., 1979)
327:(Books for Industry, New York, N.Y., 1979)
157:
490:
125:and a high alcohol content, but are not
1032:Glass coating and surface modification
1024:
464:
13:
14:
1058:
1001:Radioactive waste vitrification
956:Glass fiber reinforced concrete
447:
437:
428:
419:
408:
383:
374:
365:
352:
339:
330:
313:
121:have an approximately neutral
1:
868:Chemically strengthened glass
306:
96:
92:Treatment of glass containers
701:Glass-ceramic-to-metal seals
7:
269:
10:
1063:
232:Testing for dealkalization
921:
853:
785:
732:Chemical vapor deposition
719:
681:
653:Ultra low expansion glass
543:Borophosphosilicate glass
525:
499:
971:Glass-reinforced plastic
633:Sodium hexametaphosphate
286:Glass container industry
53:, where alkali ions are
863:Anti-reflective coating
737:Glass batch calculation
618:Photochromic lens glass
158:Dealkalization methods
996:Prince Rupert's drops
845:Transparent materials
805:Gradient-index optics
613:Phosphosilicate glass
961:Glass ionomer cement
835:Photosensitive glass
762:Liquidus temperature
583:Fluorosilicate glass
276:Corrosion of glasses
981:Glass-to-metal seal
903:Self-cleaning glass
825:Optical lens design
966:Glass microspheres
888:Hydrogen darkening
810:Hydrogen darkening
558:Chalcogenide glass
548:Borosilicate glass
360:Corrosion of glass
347:The Glass Industry
325:Corrosion of glass
216:1,1-difluoroethane
148:borosilicate glass
1019:
1018:
936:Glass-coated wire
908:sol–gel technique
893:Insulated glazing
830:Photochromic lens
815:Optical amplifier
767:sol–gel technique
221:hydrofluoric acid
111:alcoholic spirits
1054:
757:Ion implantation
512:Glass transition
485:
478:
471:
462:
461:
455:
451:
445:
441:
435:
432:
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423:
417:
412:
406:
405:
403:
402:
393:. Archived from
387:
381:
378:
372:
369:
363:
356:
350:
343:
337:
334:
328:
317:
226:Ball Corporation
208:ammonium sulfate
47:glass containers
1062:
1061:
1057:
1056:
1055:
1053:
1052:
1051:
1037:Glass chemistry
1022:
1021:
1020:
1015:
951:Glass electrode
946:Glass databases
923:
917:
855:
849:
781:
715:
691:Bioactive glass
677:
663:Vitreous enamel
648:Thoriated glass
643:Tellurite glass
628:Soda–lime glass
598:Gold ruby glass
568:Cranberry glass
521:
495:
489:
459:
458:
452:
448:
442:
438:
433:
429:
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384:
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370:
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357:
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344:
340:
335:
331:
318:
314:
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296:Surface science
291:Soda-lime glass
272:
234:
205:
201:
196:sulfur trioxide
193:
177:
173:
169:
160:
99:
94:
83:
71:
39:soda-lime glass
12:
11:
5:
1060:
1050:
1049:
1044:
1039:
1034:
1017:
1016:
1014:
1013:
1008:
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993:
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983:
978:
973:
968:
963:
958:
953:
948:
943:
938:
933:
927:
925:
919:
918:
916:
915:
913:Tempered glass
910:
905:
900:
895:
890:
885:
883:DNA microarray
880:
878:Dealkalization
875:
870:
865:
859:
857:
851:
850:
848:
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842:
837:
832:
827:
822:
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807:
802:
797:
791:
789:
783:
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779:
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769:
764:
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752:Glass modeling
749:
744:
739:
734:
729:
723:
721:
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708:
703:
698:
693:
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683:Glass-ceramics
679:
678:
676:
675:
670:
665:
660:
655:
650:
645:
640:
635:
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625:
623:Silicate glass
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550:
545:
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494:science topics
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233:
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191:
188:sulfur dioxide
175:
171:
167:
159:
156:
152:ionic strength
98:
95:
93:
90:
81:
69:
34:resistance.
17:Dealkalization
9:
6:
4:
3:
2:
1059:
1048:
1045:
1043:
1040:
1038:
1035:
1033:
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858:
852:
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843:
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838:
836:
833:
831:
828:
826:
823:
821:
820:Optical fiber
818:
816:
813:
811:
808:
806:
803:
801:
798:
796:
793:
792:
790:
788:
784:
778:
777:Vitrification
775:
773:
770:
768:
765:
763:
760:
758:
755:
753:
750:
748:
747:Glass melting
745:
743:
742:Glass forming
740:
738:
735:
733:
730:
728:
725:
724:
722:
718:
712:
709:
707:
704:
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694:
692:
689:
688:
686:
684:
680:
674:
671:
669:
666:
664:
661:
659:
658:Uranium glass
656:
654:
651:
649:
646:
644:
641:
639:
638:Soluble glass
636:
634:
631:
629:
626:
624:
621:
619:
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611:
609:
606:
604:
601:
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584:
581:
579:
576:
574:
571:
569:
566:
564:
561:
559:
556:
554:
553:Ceramic glaze
551:
549:
546:
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541:
539:
536:
534:
531:
530:
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524:
518:
515:
513:
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486:
481:
479:
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467:
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463:
450:
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422:
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397:on 2007-12-12
396:
392:
386:
377:
368:
361:
355:
348:
342:
333:
326:
322:
316:
312:
302:
301:Glass disease
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297:
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292:
289:
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282:
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261:
255:
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164:
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128:
124:
120:
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112:
107:
105:
89:
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79:
75:
67:
63:
58:
56:
52:
48:
44:
40:
35:
33:
29:
26:
22:
18:
986:Porous glass
941:Safety glass
898:Porous glass
877:
856:modification
668:Wood's glass
588:Fused quartz
563:Cobalt glass
517:Supercooling
449:
439:
430:
421:
410:
399:. Retrieved
395:the original
385:
376:
367:
359:
354:
346:
341:
332:
324:
315:
256:
251:
239:
235:
213:
179:
165:
161:
141:
132:glass flakes
108:
103:
100:
86:ion-exchange
59:
36:
16:
15:
1011:Glass fiber
976:Glass cloth
720:Preparation
696:CorningWare
578:Flint glass
573:Crown glass
526:Formulation
444:pp.174-180.
23:containing
1047:Containers
1026:Categories
1006:Windshield
840:Refraction
800:Dispersion
608:Milk glass
603:Lead glass
401:2007-12-14
307:References
97:Motivation
51:weathering
1042:Packaging
873:Corrosion
772:Viscosity
727:Annealing
454:1612-1617
243:autoclave
137:diffusion
78:hydronium
32:corrosion
991:Pre-preg
795:Achromat
538:Bioglass
533:AgInSbTe
270:See also
247:titrated
127:buffered
62:silicate
922:Diverse
854:Surface
711:Zerodur
252:Type II
80:ions (H
76:(H) or
74:protons
55:leached
21:glasses
924:topics
787:Optics
593:GeSbTe
500:Basics
349:(1968)
104:inside
66:silica
43:sodium
25:alkali
706:Macor
673:ZBLAN
507:Glass
492:Glass
321:bases
281:Glass
194:) or
186:with
180:bloom
144:vials
115:vodka
260:SIMS
184:lehr
117:and
88:.
68:(SiO
28:ions
264:XPS
262:or
198:(SO
190:(SO
119:gin
1028::
174:SO
123:pH
484:e
477:t
470:v
404:.
204:x
200:3
192:2
176:4
172:2
168:3
82:3
70:2
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