ISO INTERNATIONAL STANDARD 7884-1 First edition 1987-12-15 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEKAYHAPOAHAAOPIAHM3ALMAOCTAHAAPTW3ALMV Kvs ntemct De Ser Glass - Viscosity and viscometric fixed points Part 1 : Principles for determining viscosity and viscometric fixed points Referencenumbel ISO 7884-1 : 1987 (E) Standardizatiol No reproduction or networking permitted without license from IHS Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (Iso member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member bodyinterested inasubjectforwhichatechnical committeehasbeenestablishedhas the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technicat committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with iSO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7884-1 was prepared by Technicai Committee ISO/TC 48 Laboratoryglassware and related apparatus. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other Internationai Standard implies its latest edition, unless otherwise stated. C) InternationalOrganizationforStandardization,1987 Printed in Switzerland Copyright International Organization for Standardization No reproduction or networking permited without license from IHS Not for Resale ISO 7884-1 : 1987 (E) INTERNATIONAL STANDARD Glass --- Viscosity and viscometric fixed points Part 1 : Principles for determining viscosity and viscometric fixed points 0 Introduction 3 Definitions International Standard iso 7884, Glass Viscosityand For the purposes of this part of iso 7884, the following defini- viscometric fixed points, consists of the following separate tions apply. parts : 3.1 viscosity: The property of resistance to flow under Part 1: Principles for determining viscosity and viscometric stress. In the case of Newtonian behaviour, the rate of defor- fixed points. mationisproportional tothestress. Part 2: Determination of viscosity by rotation viscometers. Following internationaily used convention, the preferred unit for the viscosity of glass is the SI sub-unit decipascal second Part 3: Determination of viscosity by fibre elongation (dPa·s)*. viscometer. 3.2 Ranges of viscosity Part 4: Determination of viscosity by beam bending. With respect to practical application, three ranges of viscosity Part 5: Determination of working point by sinking bar measurement can be distinguished : viscometer. a)melting range: up to 103 dPa.s Part 6: Determination of softening point. b) working range: about 103 to 108 dPa-s Part 7: Determination of annealing point and strain point by c) annealing range: about 1013 to 1015 dPa·s beam bending. 3.3 Viscometric fixed points Part8: Determinationof (dilatometric) transformation temperature. It is convenient to specify the following five temperatures to characterize the viscosity-temperature behaviour of a glass. Scope and field of application NOTE -- The expression "fixed point" does not denote any relation- 1 ship to thermodynamical fixed points. This part of iSo 7884 gives rules for characterizing glass as a 3.3.1 working point 1 : The temperature corresponding to liquid (or liquid-analogue deformable) material with respect to its dynamic viscosity n and viscosity-temperature relationship, a viscosity if it behaves as a Newtonian fluid. nf1 = 104 dPas NOTE--Non-Newtonian behaviour maybe observed sometimes in to be determined by one of the methods described in opaque glasses,vitreous enamels or highly crystalliz