Because glasses have particular properties

for example it is easy to be fabricated into products with various shape in the range from bulk plate to fine fiber

and many key optoelectronic components

e.g.

amplifier

display and storage devices etc.are made of glass with special optical properties

therefore we think the studies on long lasting phosphorescent (LLP) glasses and glass ceramics are important in views of not only the traditional application of LLP materials

but researching of new optoelectronic materials and devices.This article introduces the study on a new kind of LLP material:Eu

2+

Dy

3+

co-doped strontium aluminoborate glass-ceramic with a composition of 29% B

2

O

3

28% Al

2

O

3

43% SrCO

3

0.1% Eu

2

O

3

and 0.1% Dy

2

O

3

(mol%).TransparentEu

2+

Dy

3+

co-doped strontium aluminoborate glass with the same composition was synthesized under a CO atmosphere at 1550℃ which didn’temit LLP

however

opaque glass-ceramic with LLP phenomenon was formed by appropriate heat-treatment to glass.The XRD and infrared analysis show that the main microcrystalline phase in the sample is SrAl

2

O

4

.The excitation spectrum of the sample shows a broad band peaking at about 366nm which is due to the f→d transition of divalent europium; the emission spectrum is alike with the long lasting phosphrescent spectrum

showing a band which peaks at 516nm attributed to 5d→

8

S

7/2

transition of divalent europium.Thus the LLP of the sample is due to the characteristic emission of Eu

2+

ion.The thermoluminescence spectrum consists of three Gaussian fitted components

which may indicate there exist three kinds of traps.When the glass ceramic is irradiated with fluorescent lamp with a power density of 1.2×10

4

lx for 20 minutes

the luminance of the sample is 3.53cd/m

2

10 seconds after stopping the irradiation

the chromaticity coordinates are

x

=0.2842

y

=0.5772.After 5 hours of the irradiation

the sample still has a luminance of 0.01cd/m

2

.The phosphorescence can be seen in dark even 30 hours after the irradiation.The decay of the luminescence is a complex process that consists of three parts: a fast decay

a intermidate and a long decay process.We considered that the formation of SrAl

2

O

4

micro crystal was essential for the LLP of glass ceramic

it was very possible that Eu

2+

and Dy

3+

ions were incorporated in the SrAl

2

O

4

micro crystal

thus the LLP of glass ceramic was emitted by Eu

2+

Dy

3+

co-doped SrAl

2

O

4

micro crystal.However

directly proof showing the formation of SrAl

2

O

4

:Eu

2+

Dy

3+

was absent.We suggest the LLP is due to the recombination of trapped holes and electrons which

c

an be thermally released from trapping centers at room temperature.However

further studied should be carried on the mechanism of the LLP of Eu

2+

Dy

3+

co-doped strontium aluminoborate glass ceramic

as well as the relationship between the treatment processing of glass ceramic and its phosphorescent properties.