ISO INTERNATIONAL STANDARD 7884-3 First edition 1987-12-15 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION ME>KAYHAPOAHAAOPTAHM3ALMHOCTAHAAPTW3ALMM ANEaexcDoSect Glass - Viscosity and viscometric fixed points - Part 3 : Determination of viscosity by fibre elongation viscometer Referencenumber ISO 7884-3 : 1987 (E) Standardizatio 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 body interested in a subject for which a technical committee has been established has 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 technical 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 7884-3 was prepared by Technical Committee ISO/TC 48, Laboratory glassware 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 International Standard implies its latest edition, unless otherwise stated. @InternationalOrganizationforStandardization,1987 Printed'in Switzerland' No reproduction or networking permitted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 7884-3 : 1987 (E) Glass - Viscosity and viscometric fixed points Part 3 : Determination of viscosity by fibre elongation viscometer 0 Introduction formulae over the whole range of giass viscosities and for a more detailed survey on thermal history influences than can be International Standard ISo 7884, Glass - Viscosity and derived from fixed-point methods alone. viscometric fixed points, consists of the following separate parts: 2 Field of application Part 1: Principles for determining viscosity and viscometric fixed points. The method is applicable mainly in a viscosity range from 108 to 1013 dPa-s* but special devices might be able to extend the Part 2: Determination of viscosity by rotation viscometers. range up to 1014,5 dPas. This corresponds to a range of temperature from 800 to 400 oc for all glasses of normal bulk- Part3: Determination of viscosity by fibre elongation production compositions. viscometer. NOTES Part 4: Determination of viscosity by beam bending. In the viscosity range above 1012 dPas the thermal equitibrium of Part 5: Determination of working point by sinking bar the liquid structure is noticeably delayed following a temperature viscometer. change. For tests within that range it should be agreed whether it is necessary to wait for the final equilibrium viscosity at a given Part 6: Determination of softening point. temperature, or to take the viscosity value corresponding to a conven tional temperature-time programme. In the latter case a non- Part 7: Determination of annealing point and strain point by equilibrium viscosity is denoted by nneq. The symbol n without index beam bending. denotes always equilibrium viscosity. The softening point, the annealing point, and the strain point are Part8: Determination of (dilatometric) transformation conventional temperature points (so-called fixed points), which are ob- temperature. tained by special test procedures in appropriate, well-defined ap- paratus (see ISO 7884-6 and iSO 7884-7). These points characterize the flow behaviour of glass in the range of softening and glass transi- Scope tion, but only approximate viscosity values are assignable. This part of ISo 7884 specifies a method of determining the dynamic vis